Transplant Care for Garden Plants
by Don Janssen, Extension Educator
May 10 is the frost-free date
for SE Nebraska.
Transplants are the way to go with tomatoes and dozens of other annual flowers and vegetables common in Nebraska gardens. Transplants give long-season crops a chance to produce before fall frost and mean that annual flowers begin to bloom weeks earlier than they would if they'd been planted from seed.
The key to success with transplants is selecting healthy young plants and handling them properly.
Transplants should be stocky and compact with healthy-looking foliage. Green foliage should be a rich dark green, not pale or yellow, and free of spots that might indicate disease. Colored foliage -- as on coleus, for instance -- should be free of discoloration or signs of disease. Wilted foliage may mean the plant needs water; it can also be a sign of root rot or other disease problems.
Though it's nice to see annuals or perennials in flower, the best transplants are those without flowers or fruits. Right after planting, transplants need to concentrate on establishing a large, strong root system. If they've already switched from vegetative growth to flower or fruit production, they will not be able to do this and will struggle through the season on an inadequate root system.
The shock of going directly from the sheltered greenhouse environment to the garden can stop plants' growth or even kill them. Easing transplants into the garden in stages gives them a chance to get accustomed to outdoor conditions gradually. Start by setting flats outdoors in a protected area for a few hours on warm, sunny days and decrease watering somewhat. Increase the time that plants spend outside each day for several days. This process, called hardening, reduces the amount of transplant shock the plants suffer when they're set in the garden.
At transplanting time, handle plants carefully to avoid damaging their roots and stems. If plants were grown in peat pots, soak the pots thoroughly before planting, and make sure the edge of the pot is completely covered -- if the lip is left exposed, it will wick water away from plant roots.
Plants in multicompartment containers should be well watered and removed from their cells with care and transferred quickly into the garden so their roots don't have a chance to dry out. All transplants should be watered in after transplanting so dry soil around them doesn't pull water away from their roots.
Often it isn't enough to just stick the plants in the ground and water -- newly set transplants may need protection against insects, frost and wind.
Cutworms are hairless caterpillars that snip off seedlings and transplants at or just below the soil surface. They're especially fond of pepper plants, though they may damage other plants, also. A 3- to 4-inch-wide strip of lightweight cardboard formed into a circle and pushed into the soil around each plant is usually all that's necessary to protect it.
Frost protection may be needed if warm-weather crops such as tomatoes and peppers are planted early or frost threatens after the usual frost-free date. Warm-weather crops shouldn't be planted until the soil has warmed up to 65 degrees and the average date of the last frost is past. They usually grow poorly, if at all, before that, so little is gained and the plants might be lost if they're planted too early.
Warming the soil with plastic mulch and protecting tender crops with milk jugs or commercial plant covers can extend the season and enable warm-weather crops to go into the garden before the frost-free date. Each gardener needs to balance the time, effort and expense involved against the desire to have the first red tomato on the block and make his or her decision accordingly.
Cool-weather crops such as broccoli, cabbage and other members of the cabbage family will tolerate cooler soil and air temperatures and even some light frost and so can be planted earlier.
All transplants are subject to wind damage. Commercial plant covers or caps, windbreaks of evergreen prunings and milk jugs with the bottoms cut out can be used to keep wind from flattening newly set transplants.
Even the healthiest transplants with the best handling will experience some root damage at transplanting. Until they get their roots established, the tops won't grow. To promote rooting, give plants a dose of high-phosphorus fertilizer at transplanting. Phosphorus is the most important nutrient for root growth.
University of Nebraska-Lincoln Extension in Lancaster County is your on-line yard and garden educational resource. The information on this Web site is valid for residents of southeastern Nebraska. It may or may not apply in your area. If you live outside southeastern Nebraska, visit your local Extension office