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TOO MUCH COMPOST?

GARDEN TIPS – Written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Published July 31, 2016

While both new and experienced gardeners know that garden soil may benefit from the addition of compost, they do not know about the problems that can arise when from adding too much or using poor quality compost. Let’s take a little time to chat a bit about the pitfalls of adding compost to garden soil.

While good quality compost is considered the holy grail of garden organic matter, there are no set standards for compost. The quality of compost varies with the types of materials composted and the composting processes used. Mature compost is one where the organic materials are fully broken down into stable organic matter. Quality compost is mature compost that is not high in salts, contains no contaminants from industrial waste, has few weed seeds, and can provide plant nutrients.

You can not discern quality compost by looks. If purchasing commercially made compost, ask the seller for a copy of the laboratory analysis provided by the compost producer. Look for the carbon to nitrogen ratio (C:N) that indicates the stability of the organic matter (OM). A ratio between 12:1 to 15:1 is an indication that the OM is stable. If the ratio is less than 10:1, it is an indication that it contains organic materials that are still in the process of decomposing. A ratio above 25:1 indicates that the compost contains high carbon materials that break down very slowly and will tie-up available nitrogen as it decomposes, depriving garden plants of nitrogen and hampering plant growth.

On the analysis look for the EC or electrical conductivity of the compost. This is a measure of the soluble salts in the soil. High soluble salt levels are harmful to plant roots. Compost with an EC above 8mmho/cm are high in salts and should be avoided. It is better to purchase compost with an EC that is between 0 and 4 mmhos/cm.

Also, pay attention to the percent (by dry weight) of organic matter in the compost. If the percentage is lower than 30 per cent, it means that soil or sand have been added to the mix. If higher than 60 percent, it is unfinished or immature compost containing undecomposed organic materials.

Be aware that each batch of compost that a producer makes varies in its analysis. One time the salt levels may be acceptable and the next time they may be too high, so check the analysis each time you purchase compost even if it comes from the same supplier or producer.

While local soils often benefit from the addition of quality compost, it is possible to over do it. Too much compost can cause problems including excess nutrient levels, especially nitrogen and phosphorous, high soluble salts, and excessive levels of organic matter. (Levels of organic matter above 5% to 8% by weight are too high.)

The general rule of thumb when adding compost to the soil in vegetable gardens or annual flower beds is to add no more than 2 to 3 inches of quality, low-in-salt compost to garden. The compost should be thoroughly incorporated into the top 6 to 8 inches of soil before planting. Done annually, the level of organic matter in your soil will increase. To avoid excessive levels of organic matter, reduce the amount of compost you are adding to only 1 inch after three years or get a soil test to determine the level of organic matter in your soil. As with so many things in life, too much of a good thing can be bad. The same goes for compost.

Garden Hint: How much compost do you need to apply one inch to the garden? Three cubic yards will cover 1,000 square feet to a depth of one inch.

ORGANIC MATTER CAN BE GOOD OR BAD MAGIC IN THE SOIL

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Eager first-time gardeners may be so anxious to start their garden that they fail to take the time to adequately prepare the soil. The key to garden success starts with the soil. If you have bad soil, your success will be limited.

So what’s considered a ‘bad’ soil? Soils that are compacted, or don’t drain well, or drain too well and don’t retain moisture, or don’t contain nutrients are bad soils that need help to become productive.

Organic matter is the magic potion for creating a better soil from bad soil. Organic matter (OM) improves the drainage of compacted or heavy soils by increasing the porosity. It helps sandy soils retain water and nutrients. OM also acts as a slow-release fertilizer over time, releasing nitrogen, phosphorus, and sulfur.

However, OM can turn into ‘bad magic’ if you add too much. Don’t overload the soil by applying more than one to two inches of organic matter before tilling it into the soil. Fall is a good time to add uncomposted OM to your soil, especially when starting a new garden.

The wrong types of OM will can also spell trouble. The microbes in the soil responsible for breaking down organic matter need nitrogen to reproduce. Materials with a high carbon to nitrogen (C:N) ratio will tie up all the available nitrogen. The garden plants will suffer because they can’t get enough nitrogen from the soil for healthy growth. That’s why it’s best not to use straw, straw bedding, sawdust, wood chips, or bark as the source of organic matter because they all have a very high C:N ratio.

Organic matter with a low C:N ration, such as fresh manure and grass clippings, are a good source of nitrogen, but usually aren’t as good in building the soil. Materials with a moderate C:N ratio, such as chopped tree leaves, compost, and cover crops, don’t provide as much nitrogen to plants, but do a better job of adding OM to the soil.

More Bad Magic: When adding manure from a feed lot or dairy barn, be aware that these materials may be high in accumulated salts because of animal urine. Fall is a good time to on to apply manure so winter precipitation can leach salts away.

Health Alert!… More Bad Magic: When adding manures to your vegetable garden, you risk exposing you and your family to E. coli bacteria and other pathogens in the manure. To reduce the risk, WSU recommends against using fresh manures on your garden. If you do use fresh manure on the garden, they recommend waiting 120 days after application before harvesting high risk crops and 90 days before picking harvesting for low risk crops.

High risk crops are those in direct contact with the soil and that are often eaten raw. This includes leafy greens, such as lettuce and spinach; as root vegetables, such as carrots and radishes; and vining crops left to sprawl on the ground, such as melons or cucumbers. Low risk crops are those that don’t touch the ground or that are typically cooked before eating, such as sweet corn, squash, and eggplants.

To minimize the risk it would be best to apply fresh manure to the garden in the fall of the year or use professionally composted manure from a commercial facility where hot composting was practiced.

Keep in mind that organic matter can be the magic potion that transforms a bad soil into a good, but be sure to apply the right kinds of OM, don’t add too much, and be careful when using manures.

UPCOMING CLASS: Marianne Ophardt, WSU Extension Regional Horticulture Specialist, will be teaching a Backyard Composting Workshop on Saturday, April 28 from 9:30 a.m. to noon inside the Highland Grange Hall, 1500 S. Union Street. Participants registering for this free program will receive a free composting bin and book for attending. Seating is limited. For more information or to register, call 735‑3551.

Published: 4/6/2012 9:38 AM

BIOCHAR, THE NEW BLACK GOLD FOR SOIL

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Have you heard about biochar? While some scientists are calling biochar the new ‘black gold, ‘ it’s probably not on most gardeners’ radar. The technical definition of biochar according to WSU researchers is that biochar ‘is a carbonaceous product made from the pyrolysis of organic materials (usually lignocellulosic, or woody, materials).’ They explain that it’s basically a charcoal material that’s being studied for its potential benefits when added to soil.

Studies of the black earth soils (known as terra petra) in the Amazon have revealed a high biochar-like content. The reason biochar is being studied is because it’s believed the high productivity of the Amazonian black earth soils are due to the biochar they contain.

However, scientists aren’t just interested in biochar’s potential ability to improve soil fertility and crop production. They’re also interested in other possible environmental benefits related to creating and adding biochar to soils. In the Amazon the soil biochar has stored carbon for over a thousand years. The scientists at WSU and other universities want to know if the same will apply in Washington soils and other regions. Sequestering carbon in our soils would be help slow the increase of human-caused greenhouse gas emissions. An additional benefit of biochar could be realized if it’s processed and made into activated charcoal for use in water purification.

It’s believed that the biochar in Amazonian soils was created by human agricultural activities, especially the burning of vegetation. Biochar is the result of burning, or pyrolysis as the scientists call it. Pyrolysis is defined as a ‘thermochemical conversion process for biomass materials.’ This simply means that heat is used to break chemical bonds. The heat is applied under low oxygen conditions to keep the material from burning up. Pyrolysis has been used for thousands of years to make charcoal.

Is biochar simply charcoal? No, charcoal is made using low-tech ‘slow pyrolysis.’ Biochar can be made using modern slow, fast, or flash pyrolysis processes. When materials are processed using pyrolysis, there are three products. The solid portion is biochar, but there are also both gaseous and liquid co-products. The liquid portion can be turned into a ‘green fuel’ or bio-oil and the gaseous portion (syngas) can be burned for energy production.

So what types of materials can be used to produce biochar? Almost any organic material can be used but the best candidates are low in moisture content, low in proteins, and high in lignins and cellulose. Scientists are focusing efforts on utilizing farm and forest waste products, materials such as crop residues, nut shells, wood prunings from orchards and vineyards, sawdust, wood chips, manure, grasses, and sewage sludge.

Why would gardeners be interested in someday being able to add biochar to their garden soil? I’ve already noted that better plant growth and yield is attributed to soils high in biochar, but scientists believe it may help reduce fertilizer requirements, reduce leaching of nutrients from the soil, improve soil texture and structure, improve water movement in the soil, and increase beneficial soil microbes.

Biochar isn’t available yet for home gardeners to try, but perhaps it will be in a few years. Right now scientists are researching’Black Gold’s’ total potential for reusing agricultural waste, improving the environment, producing green energy, and improving agricultural soils.

SIDEBAR:

Biochar is just one of the topics that is being presented by WSU faculty, USDA scientists, and Northwest experts at the 2012 Master Gardener Advanced‑Education Conference being held at the TRAC in Pasco on September 13 through 15. What’s exciting is that the conference is open to the public, as well as to Master Gardeners from around the state. Dr. Harold P Collins, USDA microbiologist, will be presenting a class on ‘BIOCHAR – Agriculture’s Black Gold? The Promise of Biochar’ at the conference.

Other exciting classes for gardeners include: Grafting Vegetables; Bat Ecology; Columbia Basin Ecology and Flora; Growing Backyard Blueberries; Growing Grapes for the Table, the Bottle, and the Arbor; The History and Future of the Potato; Drip Irrigation for the Yard and Garden; Straw Bale Gardening; Pollinator Ecology; Vegetable Gardens: An Edible History; and more. Natural history buffs are sure to like ‘MCBONES

Coyote Canyon Mammoth Dig’ and ‘Transforming the Landscape and Soils of the Inland Northwest: the Ice Age Missoula Floods.’ To learn more about the conference and to register on-line go to http://mastergardener.wsu.edu/mgfws/advtraining.htm

Published: 8/10/2012 1:49 PM

EARTHWORMS NO JOKE

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

I started as a WSU Extension educator on the first day of April in 1980. One of the first calls I received was from a gardener wanting to kill the earthworms in his lawn. Where I came from in New York state earthworms were considered valuable creatures. I wondered if the call was an ‘April Fools’ joke because I hadn’t yet encountered the mounds of soil that nightcrawlers caused in local lawns, making walking across them difficult.

Many have revered earthworms for their recycling of organic matter and building a better soil. Ancient Egyptians declared earthworms to be sacred because of their contributions to agricultural production. While forbidding Egyptian farmers from touching the ‘sacred’ worms might seem silly, USDA research supports that earthworms were critical to the soil fertility of the Nile Valley of ancient Egypt.

Well known natural historian and the father of the theory of evolution, Charles Darwin is not widely known for his earthworm studies. Darwin recognized the value of the earthworm saying, “Without the work of this humble creature, who knows nothing of the benefits he confers upon mankind, agriculture, as we know it, would be very difficult, if not wholly impossible.” His book, ‘The Formation of Vegetable Mould Through the Action of Worms, With Observations on Their Habits,’ published in 1881, was a better seller than his previous book on the origin of the species.

While respected and valued for their soil building efforts, there is now concern that the many of the earthworms that are recycling organic matter in our agricultural fields, gardens, and compost piles are actually non-native species. In fact, research indicates that the worms creating bumps in lawns, being pulled from the ground by birds, and surfacing on sidewalks during wet weather are predominantly non-native species. WSU and University of Idaho researchers checking out earthworm populations in the Palouse area have found that non-native species of earthworms predominate in both home gardens and agricultural lands.

Why the concern? Scientists are worried about non-native earthworms because they’re so ‘good’ at recycling organic matter, maybe a little too good. In the Great Lakes area of the northeast, these over-achieving non-native worms have invaded hardwood forests that don’t depend on earthworms to recycle organic matter on the forest floor.

The invading worms are removing organic matter that would have decomposed more slowly, releasing nutrients and contributing to the growth of native species. The activities of the non-native earthworms have significantly changed the ecosystem and led to an increase in invasive plant species and a decrease in the diversity of wildlife. Studies indicate that the Lumbricus species, including the robust night crawler, are the most destructive.

Some scientists conjecture that earthworms are contributing to global climate change. Yes, really. Current research is studying whether the worms help sequester carbon in the soil with their recycling activities or if they’re actually releasing it into the atmosphere.

Locally, it’s the bumps in the lawn that are a problem. Unfortunately, there are no chemicals recommended for their control. If you have a nightcrawler problem, you can use a dethatching power rake in early spring to break up the mounds by setting the teeth so that they only go deep enough to break up the mounds without tearing up the grass. Because the worms don’t like dry soil, irrigating less frequently and allowing the top couple of inches to dry out may help discourage their mounding activities. I’ve learned that nightcrawlers in the lawn are no joke.
Published: 4/13/2012 9:49 AM

RESOLUTIONS FOR GARDENERS

written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

Happy New Year! To tell you the truth I’m never been one of those people who makes New Year’s resolutions. It’s because I’m not sure I could keep them. However, here are a few gardening resolutions I’d like to keep… if I made resolutions.

Keeping a Garden Journal: I admire gardeners who keep meticulous records of what varieties they plant where in their gardens, make notes of when they planted seeds or transplants, record the daily or weekly weather, remark on problem pests, and write about garden successes and failures. As much as I’d like to do that and have even procured a very nice garden journal, I haven’t written down one word.

Of course writing a journal with pen and paper is somewhat outdated today. I could journal with an on-line blog, on a Facebook page, or by twittering. I could even take pictures with my phone’s camera to record the good and the bad. I just might do that, but mind you I’m not making it a resolution.

Buying Only the Seed I Need: I don’t buy much seed anymore since much of my garden consists of perennial plants, ornamental grasses, and flowering shrubs, but when I peruse through seed catalogs I almost can’t resist buying veggies and annual flowers I’d like to try. This is a real problem every year for many gardeners. It’s always fun to try something new, but there’s only so much room in anyone’s garden!

I have the same problem when I find an interesting new plant. I want to buy it without thinking about whether I have the space for it or if it will fit into my design. This is the downfall of many gardeners like me who love plants. Last year I resolved not to keep buying plants just because I was smitten. I amazed myself when I was at a local nursery last summer poised to buy this gorgeous Japanese forest grass variety called ‘Beni-kaze.’ My resolve held and I decided to go home and check to see where I could plant it. Couldn’t find a spot, but I’ll be back for it when one opens up.

Soil Testing: One resolution that I am making is to get my soil tested. Even though I recommend that gardeners get their soil tested, I haven’t followed through myself. A soil test checks the levels of the nutrients in the soil that are essential for plant growth. The soils lab that tests the soil will provide me with a report regarding the level of these nutrients in the soil and indicate the amount of fertilizer needed for good plant growth.

Without a soil test, we gardeners are just guessing what nutrients are needed and are probably over applying some and under applying others. Excessive applications of certain nutrients, especially nitrogen and phoshorus, can cause harm to plants and the environment.

Take Time to Smell the Flowers: Dedicated gardeners can always find something to keep them busy in the garden and usually fail to relax and enjoy what their hard work and loving attention has created. I think more of us should resolve to forget the deadheading, weeding, and watering for a little while each day and take time out to enjoy our gardens. If you don’t have a garden of your own, take a walk through the Master Gardeners Demonstration Garden behind the Kennewick Library on S. Union in Kennewick. There’s always something to see… even in the winter.
Published: 1/6/2012 1:24 PM

MY FIRST GARDEN – SOIL PREPARATION

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

The “ideal” soil for vegetable gardening is one that is slightly acid, well-drained, and fertile. The ideal soil has sufficient levels of decayed organic matter is also deep, loose, and free of weeds and disease organisms.

Unfortunately for us gardeners, the “ideal” garden soil is just that, an ideal. Good garden soil is developed over time. There are no magic additives and no quick fixes that will instantly change regular or bad soil into the perfect garden soil. However, even less than perfect soils can be coaxed into growing productive gardens.

First, I would recommend getting a soil test done at one of the local soil testing labs. A soil test gives you a starting point regarding soil fertility, pH, and organic matter content. Based on past experience, I predict your soil will be slightly to moderately alkaline. This is typical for local home garden soils. One home garden soil test that I recently reviewed revealed a pH of 8.2 and another had a pH of 7.9. Both soils were within a range where most vegetables will grow without any problem.

Your soil will also most likely be low (less than 1 per cent) in organic matter and lacking nitrogen. Depending on the soil type and past fertilizing practices in the area, the soil may or may not be lacking phosphorus or potassium. Knowing your current nutrient levels will help you avoid adding unnecessary fertilizer and avert a buildup of excessive amounts of these nutrients.

While there is no magic additive, your best path to building a good garden soil is the addition of organic matter. In sandy soils organic matter helps improve water and nutrient retention. In heavier soils, organic matter aids in aeration and drainage.

Organic matter may sound like that magic additive that I mentioned earlier, but the improvement process is gradual. Only about two to three inches of organic matter should be added to the soil each year and mixed in with the soil to a depth of six to eight inches. Mulching with organic matter during the summer is also a great way to help add organic matter to the soil.

So what qualifies as organic matter. There are a variety of plant-derived materials that qualify as “organic matter,” such as compost, grass clippings, chopped leaves, coconut coir, and peat moss.

It’s not advisable to add woody materials, such as sawdust or wood chips, conifer needles, animal bedding, or straw to your garden soil as sources of organic matter because they’re considered high in carbon and low in nitrogen. It takes a long time for them to decay. Soil microorganisms responsible for breaking down organic matter can use up all the available nitrogen in the soil when “eating” high carbon materials. With no available nitrogen, your garden plants will have a hard time growing without extra applications of nitrogen fertilizer. Also, caution should be taken when using grass clippings if pesticides have been used on the lawn. Manures can cause problems because they often contain weed seeds.

My recommendation is to use quality compost that you make yourself or purchase from a local nursery supplier. Add organic matter to your garden soil every year and you’ll build a better soil.

Published: 4/16/2011 10:26 AM

IRON CHLOROSIS PART TWO

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Back in July, I promised to followup with information on solving the problem of iron chlorosis due to alkaline soil conditions. I know many of you have been on pins and needles waiting so here we go…

In an ideal world, we gardeners would have a soil test done before planting our landscape. A soil test would tell us the pH (acidity/alkalinity), as well as potential lacking nutrients needed for healthy plant growth. In that same perfect world, we would avoid planting plants not well suited to our local alkaline soils, such as rhododendron, blueberries, silver maple, and pin oak.

In reality, few of us check our soil pH before planting or selecting our landscape and garden plants. With that said, what can we do to mitigate the problem of iron chlorosis due to alkaline soil?

First, gardeners should check to see if high pH is the problem. Similar symptoms of chlorosis can be produced if the plants are over-watered, under-watered, growing in compacted soil, or have failing root systems. This means reviewing cultural practices AND having the soil tested.

The addition of elemental sulfur to the soil after planting is not recommended. This can help if done before planting, but not after. Sulfur does not dissolve. It’s ground into fine particles and mixed into the soil where only the soil in the immediate area of each sulfur particle is acidified. Sulfur applied at the surface doesn’t work its way down into the root zone where it’s needed.

Experts recommend several options for addressing the problem of alkaline soil. First is mixing equal parts of ferrous sulfate and elemental sulfur and putting the mix into holes placed in the root zone of trees and shrubs. Over time (months and years) this mix will acidify the soil close to the holes and the effect may last several years. (Examples of products with iron sulfate plus sulfur are Copperas, Jirdon Super Iron Green, Hi Yield Soil Acidifier Plus Micros, and Fertilome Soil Acidifier Plus Iron.)

A costlier route is adding iron chelates to the soil in the same manner. An iron chelate is a material where the iron molecule is protected by a larger molecule. This larger molecule keeps the iron in an available form until it is broken down by soil microbes and soil alkalinity. The response to the iron chelates is quicker, but will not last as long as the sulfur/ferrous sulfate mix. (Look for iron chelates with the FeEDDHA molecule. This includes Monterey Sequestar Iron 6%, Sequestrene 138 and Millers Ferriplus.. Other iron chelates for soil application are available, but don’t work well when the pH is above 7.2.)

If a quick fix is desired, there are iron chelate materials that are applied as sprays to the leaves. The leaves green up quickly, but this is primarily a cosmetic treatment and does nothing to help solve the underlying problem of high pH. Leaf response from chelate sprays can be uneven and the “greening up” may not last all season, especially if there is new growth after application.

Some garden stores may recommend the use of aluminum sulfate to acidify the soil. Repeated use of this product can lead to aluminum toxicity and isn’t recommended. Materials injected into the trunk of a tree are also ill advised since they create wounds that can result in wood rot.

The iron applications I’ve mentioned are worth a try, but if they don’t work, consider replacing the chlorotic plants with ones that are more tolerant of alkaline soils.

Published: 9/18/2010 1:29 PM

THE FINAL STEPS IN GETTING YOUR GARDEN GROWING

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Whew, I know it’s a lot of work, but there’s just two more steps before you can plant your veggie garden. Once you’re finished working up the soil, your final steps before planting are raking and setting up irrigation. Use a garden rake to make the soil surface level and smooth for planting. Raking with the tines pointed down helps you remove any rocks or debris that came to the surface with tilling. Use the rake with the tines pointed upwards to assist you in creating an even surface.

As soon as you plant, seeds will need water for germination and plants will need water to grow. In our dry region, gardeners can’t rely on natural precipitation to provide anywhere near enough water. That means irrigation of some sort is required. While this is the point when you set up your irrigation system, it should be considered much earlier in the planning stages.

There are numerous options, but drip irrigation, drip tape, or soaker hose are three good options. All three help conserve water and minimize both weed growth and disease problems. Of course, sprinkler irrigation is also a viable option.

Soaker hoses are hoses with tiny holes from which water trickles out or hoses with porous walls from which water oozes out. These are less expensive than a drip system, pretty simple to set up, and work best in row or bed situations where plants are close together. They’re also easier to flush out and clean if you’re using irrigation water.

Drip systems are more flexible and work well if you have a complicated garden plan with plants at varying spacings or locations. If managed properly, they’re also the best at conserving water. However, drip systems tend to be more expensive to set up and must be managed very carefully. Drip emitters have a tendency to become plugged, especially when using irrigation water. Careful attention is needed to prevent plant stress that can result when emitters become plugged. Whatever system you chose, set it up and make sure it works before planting.

Yippee! Finally we’re ready to plant. Many novice gardeners make a trip to the garden store for transplants. The convenience of garden store transplants can’t be beat. They’re definitely an advantage in getting a head start on the season with warm-season crops like tomatoes and peppers. Crops that do well as transplants include certain warm -season crops, like tomatoes, peppers, hot peppers and eggplants. Some cool-season veggies, also do well as transplants, like cauliflower, cabbage, and broccoli

However, there are some crops that perform best when grown directly from seed. Cool season crops that are best from seed include lettuce, peas, spinach, Swiss chard, radishes and carrots. Warm season crops that do best when directly seeded in soil include corn, beans, cucumbers, squash, pumpkins, melons, and watermelon.

Check the seed packet directions for recommended time of planting, depth of planting, and spacing of seedlings. Seed packets and seed catalogs provide you with lots of valuable gardening information. Be sure to thin young seedlings to the recommended spacing so they’ll have plenty of room to grow.

Getting a new garden started is a lot of work, but it’s worth it when you see your baby green plants start emerging from the soil. It’s even better when you begin harvesting the veggies that you grew in your own garden.

Published: 2/13/2010 10:38 AM

NEXT STEPS IN STARTING A GARDEN

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Now what? You’ve decided where to place your garden and how big it will be, plus you’ve already worked up the soil. The next steps are preparing the soil and fertilizing.

STEP FOUR – PREPARING THE SOIL: Few gardeners are satisfied with their soil. Complaints range from soil that’s too heavy and poorly drained to soil that’s too sandy and dry. The solution for both these problems is the addition of stable organic matter. Good quality compost is one of the easiest ways to add organic matter to your soil. The compost should be dark and crumbly, with no identifiable chunks of bark, twigs, pieces of wood, or other items. You can usually purchase compost in bulk from a local garden center.

How much is needed? You should never add more than one-third by volume of relatively stable organic matter to your soil. That means if you’re working the soil to a depth of six inches, don’t add more than two inches of organic matter. Peat moss and coconut coir are two other types of stable organic matter that are readily available to gardeners, but both are considerably more expensive than compost. Some gardeners don’t like to use peat because there are environmental concerns about harvesting it from bog ecosystems in Canada. However, the Canadian peat industry is well regulated and harvesting is balanced with restoration practices to protect this natural resource.

If you have concerns about using peat moss, look for coconut coir. Coconut coir is a renewable byproduct of the coconut processing industry and comes from the coconut husk. It’s sold in dry compressed “bricks.” Look for the fine type, not the coarse, chunky kind, to add to your soil.

To thoroughly mix organic matter into the soil, use a spading fork. This is hard work. If you find the task too backbreaking, consider renting a rototiller. It will also come in handy for working fertilizer into the soil, which is the next step.

STEP FIVE -FERTILIZING: If you’re starting a garden in a brand new spot and adding organic matter, you’ll also want to add some fertilizer. An excellent organic fertilizer is rabbit manure. This is the perfect manure to till into the soil. It’s easy to transport and not as smelly as most other manures. You may be able to find free bunny poop advertised on-line or in newspaper ads. Start with about 20 to 30 gallons of rabbit manure per 100 square feet of garden area. Other manures will work, but they’re often bulkier and smellier, plus some will contain weed seeds that are still viable even after spending time in an animal’s digestive system.

Another great source of nitrogen and organic matter for the garden is alfalfa pellets. Alfalfa pellets are dried, ground alfalfa pressed into pellet form. Look for them at a farm and garden store. For adding to the garden soil, use only plain pellets without any additives. Spread about two to three pounds of pellets per 100 square feet of garden area and till them into the soil before planting.

I’m a big fan of bunny poop and alfalfa pellets, but there are also plenty of commercial boxed organic or inorganic fertilizers available that will help your garden grow.

Published: 2/6/2010 10:26 AM

PREPARING YOUR GARDEN SOIL

written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Seed companies and garden product marketers have noted that more and more gardeners are growing their own vegetables. While it’s still too early to plant most things in the garden, now is a great time to start getting the garden ready for planting.

Gardeners are known for complaining about two things they can’t do much about, the weather and their garden soil. Local gardeners are no exception. If we aren’t complaining about the wind, then we’re complaining about the heat, or maybe even the rain in the spring!

When it comes to soils, there’s quite a bit of variability in our region. Some gardeners have a silty loam and others like me have a fine sand. If you aren’t familiar with these terms, they refer to the texture of the soil and the size of the soil particles. Sandy soil has relatively large soil particles, silt has small particles, and clay has extremely small soil particles. There are very few clay soils in our region.

The larger the soil particle size, the more easily water enters the soil and the more quickly it dries out. The smaller the particles, the slower water enters and the slower it dries out. Also, the smaller the particles, the greater the soil’s ability to retain nutrients. Whatever your soil’s texture, you’re pretty much stuck with these physical properties. Complaining won’t help, but adding organic matter can.

In our shrub-steppe area, there isn’t much organic matter in the soil when we first start farming or gardening a piece of land. By adding fresh organic matter, we provide food for soil organisms. These organisms, including bacteria, fungi, insects, and worms, feed on the organic matter. Their feeding activity glues soil particles together. This improves the soil structure, creating a more crumbly soil that is easier to work and one that water enters more easily.

The ideal soil is one that’s dark and crumbly soil with good “tilth.” Even the very best local gardeners will have a hard time attaining and maintaining this ultimate goal, because organic matter disappears quickly under our arid climate conditions. However, that doesn’t mean we shouldn’t try!

Organic matter is indeed wonderful stuff. As you get the garden ready to plant in the spring, it’s a good time to add organic matter to the soil. Many gardeners add compost to their garden soil in the spring. While compost doesn’t provide much food for the soil organisms and contribute to soil tilth, it does help improve soil conditions. Water will enter the soil more easily and you won’t have to water as frequently.

Compost is a great way to recycle yard waste and is a good soil amendment, but fresh organic matter is even a better soil builder because the decay organisms are active in the soil. Fall is the best time for adding fresh organic matter to the soil. Two of the most common fresh organic matter sources are herbicide and weed-free grass clippings and fallen leaves. The organisms have all fall, winter and early spring to work on breaking down the organic matter.

There are other sources of organic matter that gardeners might consider incorporating into their garden soil or their compost piles. I’m often asked about adding sawdust, wood chips, moldy straw, and animal bedding mixed with manure. These are called “high carbon” or “brown” materials. The soil microorganisms involved in decay require nitrogen. When you add high carbon materials to the soil, the microorganisms use the available nitrogen in the soil for the decomposition process. This produces a nitrogen deficiency in the soil until the materials are fully broken down. To grow healthy plants, additional sources of nitrogen have to be applied to compensate for the nitrogen deficiency brought about by the high carbon organic matter. Because they break down so slowly and create a problem with nitrogen deficiency, it’s best to avoid adding high carbon organic matter to the garden or the compost pile.

Finally, a word to the wise… when adding organic matter to the soil, use no more than one-third by volume. If you spade or till to a depth of six inches, only add a two-inch layer to the top before you mix it in with the soil.

Published: 3/7/2009 2:52 PM

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