Washington State University Extension

Garden Tips

Archive for July 2013


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 7/11/2013

This has been quite a year for gardeners who are hoping for a banner crop of tomatoes and other vegetables from their gardens.

First, we had a spell of cool weather that allowed cool-season crops to prosper, but warm-season veggies like tomatoes, squash and cucumbers just shivered and refused to grow. This cool weather was followed by unseasonably high temperatures and then more cool weather.

Now that warm weather appears to be here to stay, my warm-season crops are thriving and flowering.

One of the great things about growing your own vegetables is being able to harvest them at the ‘peak of perfection,’ when they are full of flavor and nutrition. Because gardeners don’t have to worry about shipping their veggies, they can pick tomatoes when they are ripe and tasty.

Perfecting the skill in knowing when it’s time to harvest different vegetables takes some finesse and experience. Seed packets usually provide a guide of the average number of days from planting to maturity. However, this is just a ‘ballpark’ figure that will fluctuate depending on weather and other growing conditions.

Vegetable experts recommend picking your veggies early in the morning because that’s when they are the crispest, juiciest and sweetest. Be careful when harvesting

your produce. Veggies picked at their peak of perfection are quite tender. If you aren’t able to easily twist the fruit from the plant, use a knife, hand pruners or garden sheers to cut them off the plant. Take care not to bruise or scratch the skin.

It’s important to keep up with your harvesting. This encourages the plants to keep blooming and producing fruit.

Occasionally, a zucchini will hide beneath the leaves and escape harvest until it is too big for good eating. These ‘escapees’ still should be harvested and disposed of in the compost pile.

Harvesting tips

— Tomato: Pick when they have developed a uniform color for the variety. Fruit should still be firm.

— Summer squash (yellow, zucchini, patty pan): Harvest when small and tender, before the seeds start to develop. I like to harvest my zucchini before they get any longer than six inches, the same for yellow squash.

— Carrots: Get these beauties out of the ground when they reach the desired size. It’s best to lift them out of the ground with a garden fork, especially the long-rooted types, rather than pulling them. Carrots left in the ground too long, especially during hot weather, will be woody and lose their sweet flavor.

— Snap beans: As the name implies, these are best picked when they can be easily snapped in two and while the seeds are still small and not bulging. If you wait too long the pods will be tough and the beans starchy. Harvest frequently for the best quality and to keep the plants producing.

— Peppers: There are now different colored varieties, such as purple, yellow and orange, but sweet peppers are best when shiny green and about three to four inches in diameter. They still can be used after they turn red or yellow. Hot peppers can be picked when still green or after they change color.

Read more here:

Donate extra food to Mid-Columbia food banks
With local gardens starting to produce, now is a good time to remind area gardeners that any extra produce they have from their gardens can be put good use at local food banks. The food banks welcome fresh garden vegetables that will help fight hunger and provide a healthier diet to the needy in our region, plus every pound you donate can be claimed as a $1.50 deduction.

Here is a list of the local food banks. Because most are staffed by volunteers, it

s recommended that you first call to make sure they are open and available to take your donation. First United Methodist, 703 W. Clark St, Pasco, WA, 547-9731, Sat. 9am–noon

Salvation Army, 310 N. 4th Ave, Pasco, WA , 547-2138, Tues & Thurs 9am–11am

Adventist Community Service, 605 Road 36, Pasco, WA , 547-4998, Tuesday 9am–noon

Golden Age Food Share, 504 S. Oregon St, Pasco, WA , 547-8310, Monday–Thursday 8am–noon

St. Vincent DePaul Food Bank, 115 W. Lewis St, Pasco, WA , 544-9315, Wednesday 11am–4pm

Union Gospel Mission, 112 N. 2nd Ave, Pasco, WA, 845-1800, Everyday 8am–5 pm

Pasco Christian Church, 1524 W. Marie St, Pasco, WA, 531-8830, Monday–Friday 3pm-4pm

Tri-Cities Food Bank, 420 W. Deschutes Ave, Kennewick, WA , 586-0688, Monday–Friday 8am–noon

Harvest Outreach, 120 W. Railroad Ave, Kennewick, WA , 582-9064, Monday–Thursday 11am–3 pm

Tri Cities Food Bank, 321 Wellesian Way, Richland, WA, 943-2795, Monday–Friday 7:30am–11:30am

Salvation Army, 1219 Thayer Drive, Richland, WA, 943-7977, Tuesday & Thursday 9am-11am

Jericho Food Ministries, 2500 Jericho Road, Richland, WA , 627-0750, Tuesday– to Friday10am to 4pm

Jubilee Ministries Food Bank, 1429 Stacy St, Prosser, WA , 786-3033 or 781-0976, Tues, Wed, Thur & Sat 9am–noon

Tri-Cities Food Bank, 712 10th St, Benton City, WA , 588-5454, Wednesdays 9:30am–11:30am, Thursdays Noon to 2:30pm and 6-8pm

Connell Food Bank, 124 N. Columbia, Connell, WA , 234-0243, 2nd and 4th Weds of Month 9am–11am

Read more here:

Published: 7/11/2013 3:16 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 7/4/2013

Garden hoses can be vexing things. They are heavy and a nuisance to haul around the yard, plus they can kink. Nevertheless, they are an essential gardening tool. Last year when we needed a new one, I did not do much research and bought what seemed to be a long-lasting quality hose. The problem was that it weighed a ton and became a chore to move.

I should have taken more time to do my homework. Here’s what I’ve learned:

Garden hoses typically come in two diameters, 5/8 inches and 3/4 inches. You even can find hoses that are one inch in diameter. Many gardeners find that a 5/8 inch hose is adequate for their purposes. The 3/4 inch hoses tend to be more expensive and heavier.

Garden hoses also come in different lengths, from 25 to 100 feet long. Of course, the longer the hose, the heavier and the more costly. (Notice the trend?) The longer the hose, the lower the volume of water per minute that it delivers. To calculate this, go to:

The material a hose is made out of also greatly influences its price. As with any garden tool, the better the quality, the higher the price. Rubber and PVC reinforced hoses generally are more expensive and more flexible. High-end reinforced hoses are more resistant to abrasions, punctures and bursts. You also will find that the more a hose is reinforced, the higher the cost and the heavier the hose. The best-quality hoses will have hexagonal or octagonal brass couplings.

There also are coiled hoses. These are typically 3/8 inch diameter and usually come in 25- or 50-foot lengths. They are made out of polyurethane. They are lighter, easy to get out and use on the patio for watering containers, but they tend to kink when extended and often tangle when coiled.

Quality garden hoses can be pricy. To keep your hose in good condition, here are some tips:

1. Store your hose where it will be protected from degradation by ultraviolet light.

2. Don’t leave the hose where cars or bikes will run over it.

3. Don’t let your hose kink, causing a spot that will be weak.

4. Drain and coil your hose after every use, coiling it into loops about 24 to 36 inches in diameter. Store the coiled hose flat and off the ground in a container like a hose pot. Hanging a hose from a single hook can damage the walls of the hose, so use an arched hose rack. There are also hose reels that can be used to coil and store hoses.

5. Drain the water from the hose before it freezes in the fall and then store it in your garage or storage shed over the winter.

Safety note

Many garden hoses, especially older types, have been deemed unsafe for use for drinking water because of harmful chemicals and heavy metals that they contain. While many of the new hoses today are labeled as safe for drinking water, it’s still best not to make a practice of drinking from them because germs, molds and bacteria can build up inside.

Read more here:

Published: 7/4/2013 3:11 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 6/27/2013

I am not immune to the unpleasing and bothersome damage caused by garden pests. Here’s what’s bugging me in my garden:

The tobacco budworm is an insidious creature that eats holes in my petunias even before they open, leaving them holey and tattered. The tobacco budworm (Heliothis virescens) is the caterpillar of a medium sized (1.5 inches across) greenish brown moth. At night, adult female moths lay eggs on the buds of garden flowers. These eggs hatch into larvae or caterpillars that nibble their way into flower buds and flower centers. When feeding is severe, the flowers may not open at all.

The caterpillar can be elusive, varying in color from light green to red or brown, partly because of the color of the flowers that it is eating. It is hard to find budworms during the day because they are hiding at the base of the plants. There is a better chance of encountering them at dusk, when they come out to eat.

It was once thought that the tobacco budworm would not overwinter here, but mild winters and a lack of deep frost have allowed it to become established in some area gardens, like mine. Control is difficult because it is resistant to most garden insecticides.

The newer synthetic pyrethrin insecticide sprays are the materials most likely to be effective.

If you would rather use an organic insecticide, Bacillus thuringiensis, also known as ‘Bt,’ is an alternative. This a bacteria that disrupts the guts of moths and caterpillars, but to be effective, it must be applied where the caterpillars will ingest it.

The budworm isn’t the only culprit attacking my flowers. Another caterpillar is infesting the daisies and its relatives: the sunflower moth (Homoeosoma electellum). The larvae, or caterpillars, of this moth attack sunflowers and other members of the aster family.

An examination of infested flowers reveals mats of webbing in the center. When you tear apart the center, there is more webbing and caterpillar frass. The adult female sunflower moth is nocturnal and lays its eggs at the base of flowers just starting to bloom, laying about 30 eggs a day.

The eggs hatch in two to three days, and the larvae begin eating pollen and flower parts, and then eat their way into the center and base of the flower. Young larvae are yellow but later change to brown or purple with whitish longitudinal stripes. After about two weeks, they change into a moth.

Control of the sunflower moth is the same as with the tobacco budworm: sprays of Bt or synthetic pyrethrins at dusk. These should applied two more times at five days intervals.

Read more here:

Published: 6/27/2013 3:09 PM


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

What’s bugging you? Our mild winter and extraordinary cool weather this spring has allowed some garden insect pests to thrive. One group of these pests is what I call ‘nasty little suckers’ or aphids.

The thing that makes aphids so insidious is that most are ready and waiting to attack as soon as new growth starts to emerge in the spring, plus they have an extraordinary capacity to multiply quickly. A wingless adult female aphid is capable of producing 50 to 100 all female babies without needing to mate or lay eggs first.

These baby girl aphids quickly mature into adult females and start producing their own babies in about a week with each of those producing babies… and it goes on and on. It’s not hard to believe that just one overwintering aphid can translate into thousands within weeks. If gardeners aren’t vigilant, a small population of aphids can quickly get out of control.

Identifying aphids isn’t as easy as you might think, since they do vary in appearance. Many gardeners are familiar with green aphids and are surprised to find that there are also black, pink, yellow, blue-gray, and whitish aphids. Aphids have pear-shaped soft bodies and are usually less than 1/8 inch in length. Most aphids don’t have wings unless their population becomes crowded and they need to find a new feeding site.

Aphids have piercing-sucking mouthparts that allow them to tap into and suck out plant sap. They often excrete a sugary liquid called honeydew, leaving sticky, shiny spots on lower leaves and objects beneath, such as cars beneath aphid infested trees. When checking for aphids examine the stems and leaf undersides of new growth,. Aphids don’t scurry away like many other insects, they just keep sucking away.

Besides the bother of honeydew, aphid feeding can injure plants if an infestation is severe. As a result of heavy aphid feeding leaves may turn yellow. Many aphids also inject their saliva into the plant causing curling, stunting, puckering, and distortion of new growth. Aphids also damage some plants by transmitting viruses via their feeding.

What can you do about an aphid problem?

1. A forceful spray of water will knock aphids off a plant and those knocked off will not go back to the plant. Doing this periodically can keep modest populations under control.

2. Work with nature by encouraging natural predators like ladybugs and their larvae and not using pesticides harmful to beneficial insects.

3. Aphids are fairly easy to kill, but many softer or organic insecticides such as insecticidal soap only work when they directly contact the aphids’ bodies. When using these materials its important to apply them where the aphids are located, often on the undersides of the leaves. If aphid feeding has already caused leaf distortion, the aphids stay protected inside the curled leaves and these materials are not very effective.

4. There are systemic insecticides available, applied as sprays to the leaves or as drenches to the roots, that get into the plant sap and kill the aphids when they feed. This is the only way to kill aphids protected by curled leaves. However, most of these products are only labeled for use on ornamental plants, not fruits or vegetables.

5. If the aphids are on a woody plant, consider applying a delayed dormant oil spray early in the spring just before the buds open. This can kill overwintering aphids before they get a chance to start feeding or multiplying.


Shhh! It’s the Secret Garden Tour. Next weekend is your opportunity to take a self-guided tour to see some of the prettiest and unique gardens in the area. The Academy of Children’s Theater (ACT) Secret Garden Tour is holding their 15th annual garden tour that will take you to six beautiful local gardens, each with a special title reflecting its theme. New this year, will be performances or demonstrations by a variety of local musicians and artists at each garden. The tour runs from 11:00 a.m. to 4:00 p.m. on Saturday, June 29th and Sunday, June 30th. You can purchase tickets for $15 at ACT (213 Wellsian Way in Richland), Heritage Nursery, Wood’s Nursery, or on-line at The funds raised by the tour support ACT’s programs and classes.

Published: 6/21/2013 2:55 PM


>written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 6/14/2013

Our unusually cool spring weather has slowed down our gardens a bit , but has area lawns looking pretty good. However, once hot weather arrives a few problems will probably start appearing. Here are some tips on keeping your summer lawn healthy and looking good.

When the temperatures climb, dry spots in lawns often appear. It’s best to investigate the causes of these dry spots, rather than just increase the frequency of your watering. Possible causes of localized dry spots include poor sprinkler coverage; compacted soil; buried objects like rocks or construction waste; or hydrophobic conditions.

To check your sprinkler coverage, place some empty straight-sided cans (soup or tuna cans) inside and outside of the dry spot. Run your sprinklers for a set amount of time and then compare the amount of water in the cans and see if there is significantly less water in the cans located within the dry spots. If there is, determine the cause and fix it.

You can stick a long screwdriver into the soil to check for soil compaction and buried objects beneath the soil. (Occasionally, unusual things get buried during the construction of a home.) If compaction is a problem, consider aerating the area with core aerating equipment.

Hydrophobic means the lawn or soil resists wetting. This can be caused by excessive thatch that has dried out or a soil that is hydrophobic. Check for thatch. If the thatch is greater than one-half inch think, you should plan on power raking it next spring. To help water penetrate in areas of the lawn that are resisting wetting, core aerate to physically open up the grass and soil. Then apply a horticultural wetting agent.

A horticultural wetting agent is a nonionic surfactant chemical that breaks the surface tension of water and helps the water penetrate the hydrophobic thatch or soil. Monterey Lawn & Garden sells a wetting agent combined with fertilizer for home lawns called ‘Perc‑O‑Late Plus.’ Scotts company offers their ‘Lawn Builder +Wetting Agent’ which also contains fertilizer and a wetting agent. These should be applied according to the label directions.

With warmer weather your lawn won’t be growing as fast as early in the season, but it’s still important to mow it regularly at the recommended height. The recommended height for bluegrass (or mixes with bluegrass) lawns in our area is 2 to 2.5 inches. It’s also important to mow at the right height using a sharp mower blade.

When you don’t mow often enough you will ‘scalp’ your lawn. Scalping is the result of removing more than one-third of the grass height in one mowing. This injures the grass plants and causes them to use stored food reserves for new growth. Repeated scalping severely weakens grass, leading to the grass thinning out and weeds invading.

When a dull mower blade is used to cut the grass, it tends to shred the tips of the grass. If your blade is dull, the lawn will probably have a whitish cast to it right after you mow. This is aesthetically unpleasing and damages the grass, making it more susceptible to drought and disease.

Another cornerstone to keeping your lawn healthy during the summer is watering correctly and encouraging deep roots by watering less frequently and more deeply… but that’s a topic for another day.

Published: 6/14/2013 2:51 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 6/7/2013

As a gardener who delights in fanciful garden gnomes, I don’t know why I haven’t yet embraced fairy gardening. Fairy gardening is a huge new gardening trend being promoted by garden centers around the country.

If you haven’t already investigated it, fairy gardening is simply gardening in the miniature. It’s not unlike the terrariums and dish gardens of the 60s and 70s era, but fairy gardens are decorated with small fairy figurines, miniature structures, furnishings, and accessories. It’s sort of like having a doll house but the ‘house’ is actually a miniature garden in a container or a small area of your garden.

Is it just a gimmick by retailers to sell more stuff to gardeners? Perhaps, but it might also appeal to a long-buried desire to soar with a capricious flight of fancy. My grandmother used to tell me the most delightful stories about little fairies hiding under the leaves in the garden!

Miniature gardening is not new. The Chinese may have been the first miniature gardeners with the art of penjiing, which means ‘pot scenery.’ Penjing is an ancient Chinese art practiced during the Tang Dynasty (618-907 AD) that involves the creation of artistically trained potted trees, as in bonsai, but can also include other plants, rocks, structures, and figurines.

How do you start a fairy garden? First you must decide if you want your fairy garden in a pot or tucked away in an out-of-the-way spot in the garden. (Keep in mind that fairies prefer to stay hidden, so they avoid high traffic areas.) In our region, you will probably want your miniature garden located where it will get afternoon shade.

If you select a pot or container, it should have drainage holes in the bottom. A container that’s wider than tall gives you more space to create a landscape, but a smaller volume of soil. (The less soil, the more frequently you’ll have to water. ) You’re already tapping into your whimsicality, so it should not be hard to come up with some imaginative container ideas, like a wooden drawer, an old suitcase, or a rusty wheelbarrow. Just make sure they have adequate drainage. Fill whatever container you use with a quality, well-aerated potting mix.

Next comes your selection of plants. Local nurseries that are promoting fairy gardens should have some suggestions. If you have a fairy garden that can’t easily be taken indoors for the winter months, you will need to consider the plants’ cold winter hardiness. This is very important if your plants are in containers because the soil is more likely to freeze. When choosing plants, also consider ones with similar needs for light and water.

There are a variety of plants that can be used for fairy gardening, but you will want to select ones that stay diminutive in stature and width. Dwarf plants and plants with small leaves should be considered. Some ideas include herbs (especially thyme and dwarf rosemary), ajuga, creeping sedums, dwarf hosta, dwarf conifers, dwarf dianthus, pearlwort (Irish moss), pink pussy toes (Antennaria), and some alpine plants.

After your garden is planted, you can then accessorize it. You should be able to find some very cute little structures, figurines, furniture and other decorations at local nurseries, craft stores, or on-line… or you can use your imagination and make your own from acorns, dried gourds, and more. Have some fun and let your whimsical fairy spirit out!

Published: 6/7/2013 2:47 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 5/24/2013

When weeds appear in the home lawn and landscape many homeowners quickly turn to chemical weedkillers to take care of the problem. Herbicides (weedkillers) kill plants. That is what they are supposed to do. When used correctly they can be an effective tool to use in weed management, when used improperly they can damage desirable plants in your landscape or your neighbors’ yards.

Before you reach for a weedkiller, here are some guidelines for using these chemical tools,

1. Read the label, the entire label, before using the product. Many of the ‘weed and feed’ products or broadleaf weedkillers contain a combination of 2,4-D, MCPP, and dicamba. Somewhere on the label of these products it will note that they should not be used in the root zone of ‘desirable trees and shrubs.’ If you have a landscape with established shade trees in the lawn or in landscape beds bordering the lawn, you will be applying these materials in the root zone of ‘desirable trees and shrubs.’

So what can you do if you have weeds and trees in your lawn? If you just have a few weeds here and there, don’t use an herbicide product over the entire lawn. Spot spray the individual weeds or dig them out. I like the ‘weed popper’ tools like Fiskars Uproot Lawn and Garden Weeder or Grampa’s Weeder ( that use leverage to pop out the weeds along with most of their roots. This avoids tedious back-breaking digging with a hand weeder.

3. Damage to plants from weed killers can also be caused by drift that occurs when sprays are applied when it’s windy. It is hard to find a calm day in this region, but you should never apply sprays of herbicides when the wind speed is over 15 mph. It’s best to wait until the wind is 5 mph or less. Also, the larger the droplet size, the less likely the material will drift off target.

2. If you’re not using a RTU (ready-to-use) product in a spray bottle, it’s wise to use a separate garden sprayer for herbicide sprays. If a sprayer is not cleaned thoroughly after using an herbicide before using it to apply an insecticide or fungicide, you can end up damaging your plants with a contaminated sprayer. To clean a sprayer:

– If you can’t use all the material you have mixed, spray it somewhere in the landscape where it won’t harm plants. Check the label to determine what areas are ‘safe.’ Do not store any mixed product in your sprayer.

– Check the product label for specific directions on how to clean the sprayer after using the product. If there are none, thoroughly rinse the tank, hoses, wand, nozzle, and any other parts with water. Spray the rinse water over a wide area that will not cause damage. Don’t dump it on the ground or down the drain.

– After cleaning the sprayer when using 2,4-D or a similar herbicide, fill the tank with water and add ammonia (1/3 cup of ammonia per gallon of water). Allow it to soak for 24 hours, being sure that the ammonia solution is also run through the sprayer and all its parts before soaking. This will remove much, but not all, of the 2,4-D from the sprayer.

I have already seen damage on local yard and garden plants this spring that could have been avoided if everyone was just being a little more careful and following these simple guidelines when using herbicides.

Published: 5/24/2013 2:44 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 5/17/2013

One of my first gardening memories is helping my grandmother cut peonies. When I close my eyes I can see those pretty rosy pink blowsy flowers and smell their sweet fragrance. Peonies are a very old garden flower. Native to Asia, they have been cultivated as ornamentals for over 2500 years in China and since the eighth century in Japan. They came to North America in the 1850s via Europe.

In the ‘old’ days, most American gardeners like my grandmother grew three types of peonies …white, pink, and red, all with double flowers. Of course these were the most common varieties planted in home gardens. The diversity of peonies readily available to gardeners today is much greater, thanks to plant breeders.

Today’s peonies come in white, pink, red, burgundy, lavender, coral, and even yellow. Gardeners can find many different garden peony (Paeonia lactifora) varieties. The varieties are classified based on their flower types which includes singles, semi-doubles, doubles, Japanese, and anemone.

Peonies do best planted in a site with well-drained soil and where they’ll receive full sun. Plants should be located where they are protected from the wind and forceful irrigation sprinklers. The tubers are usually planted in the fall, but early spring planting can also be successful, as long as the tubers are still dormant. Before planting, work the soil up to a depth of 12 inches, mixing some organic matter in with the soil at the same time.

When ready to plant, dig a hole wide enough and deep enough to accommodate the tubers. Good quality tubers have three to five ‘eyes’ or pink buds. In the fall, you should be able to find some tubers at local nurseries, but specialty nurseries like the Peony Farm ( in Sequim, Washington have a wider selection of varieties.

(I have also seen some gorgeous potted peonies available at local nurseries this spring. These are planted like other potted perennials, just make sure they are not planted too deep.)

After digging the hole, position the tuber so that the eyes are no more than two inches below the surface. Because the tuber may settle deeper in the soil after you water, you should gently firm the soil around the tuber as you plant it. If the eyes end up deeper than two inches deep, you may get a peony plant that doesn’t bloom! However, it can take two or three years before a new plant provides you with a display of flowers, so don’t get discouraged if yours doesn’t bloom the first spring after planting.

When planting be sure your peony has enough room to grow. A space three to four feet wide will give it enough room to grow and allow good air circulation. Peonies do not need or do well with frequent dividing. Many do well in the same spot for 20 years or more!

After planting, peonies are a low maintenance perennial. Keep the soil slightly moist with regular irrigation and fertilize once a year with slow-release garden fertilizer if needed. Possible pest problems are powdery mildew and thrips.

The other thing I remember about my grandmother’s peonies were the black ants attracted to the sticky sweet nectar naturally exuded by the buds. I hated the ants, but liked those pretty peonies.

Published: 5/17/2013 2:12 PM


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA
Published 5/10/2013

Now that warm weather has arrived, veggie gardeners are getting ready to plant their tomatoes. When you are out shopping for tomato plants, you may notice some pricey tomato plants labeled as grafted tomatoes. Last summer, I wrote about grafted tomatoes and their impending arrival this spring. Their recent appearance at garden centers, nurseries, and even big box warehouse stores, is prompting me to answer some questions you might have about them.

What is a grafted tomato? A grafted tomato plant is one where the top of one variety of tomato has been attached to the roots of another variety of tomato. This horticultural technique is called grafting. The top variety is the ‘scion’ and the bottom variety is the ‘rootstock.’ Special rootstock varieties have been developed with certain characteristics, such as resistance to soil-borne diseases and nematodes. Some rootstocks may also increase plant vigor and production or provide better tolerance of soil that’s too wet or dry.

What are the advantages of grafted tomatoes? University trials indicate that it’s possible to realize a 50 per cent or more increase in production with grafted tomatoes. Last year in their Demonstration Garden, Benton Franklin Master Gardeners planted two varieties of grafted tomatoes side by side with two of the same varieties that had not been grafted. By the end of the season the grafted plants were bigger and appeared more productive than the same non-grafted varieties.

Better production is wonderful, but the greatest value of grafted tomatoes for home gardeners is their use with heirloom varieties. Most heirloom tomato varieties aren’t resistant to troublesome soil-borne diseases. Grafting the heirloom scions onto specific rootstocks that are resistant to these diseases can be the difference between getting delicious fruit by the end of the season or having a dead plant. However, grafting onto any rootstock will not provide the same benefits. The rootstock must be resistant to the soil-borne diseases of the area to reap the benefits.

Is growing a grafted tomato any different than growing one that’s not grafted? Growing grafted and non-grafted tomatoes is basically the same, but how they are planted is significantly different. Grafted transplants should never be planted deeply with the roots and stem buried up to the first set of leaves. The graft must be above the soil line, not below, to realize the benefits of the rootstock.

Look at the stem of a grafted transplant and you should be able to see a line where the two varieties were joined together. Take note, this is a fragile union. Handle the grafted transplant gently. When transplanting, support both the roots and the stem, being careful not to pull on the scion stem. After you water the plant to settle the soil, make sure the graft is still above the soil line.

Note: Because the graft union is especially fragile when the plants are young, don’t transplant on a windy day. If your area is prone to wind, provide the plant protection from the wind. If your grafted transplant comes with a plastic or silicone clip at the graft union, remove it two to three weeks after planting.

Because your grafted plants may grow to be larger and more vigorous than non-grafted plants, be sure to provide the vines with sturdy support in the form of cages or staking. During the growing season remove any sprouts from the rootstock that may develop below the graft.

I successfully grafted a tomato plant on my own and will be giving that a try in my garden. I’ll let you know how it grows.

Published: 5/10/2013 2:05 PM



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