LSU AgCenter's Weekly Message

Growing Your Own Vegetable Transplants

It may be hard to imagine it right now, as we just came through come of the coldest temperatures many of us have ever seen in Louisiana, but it is or will soon be time to prepare to plant warm-season vegetables.

It’s not at all too early for things like soil sampling and, if needed, liming. If you plan to grow your own transplants, it will soon be time to seed them.

It takes about 8 to 10 weeks to grow tomato, pepper, and eggplant transplants in the winter for spring planting and about 3 to 4 weeks to grow cucumber, squash, cantaloupe, and watermelon transplants. To decide when to start seeds, count back from when you plan to transplant the seedlings into the garden.

One of the main perks of growing your own transplants is that you can choose from a more diverse range of vegetable varieties than those offered for sale locally as transplants. You can try ones recommended for this area by the LSU AgCenter, or you can branch out and try others. Varieties not previously trialed nearby may result in failure, or they may be your new favorite. When possible, look for ones with resistance to diseases common to our area.

Growing transplants does require labor and supplies, so take this into account when deciding whether to grow your own.

Not all vegetables are good candidates for transplanting. Among warm-season crops, corn, beans, and peas are almost always direct-seeded. On the other end of the spectrum, tomatoes, peppers, and eggplants are almost always transplanted. In the middle are cucurbits (cucumbers, squashes, etc.), most of which establish well when direct seeded (triploid or seedless watermelons are an exception) but can be grown from transplants for an earlier harvest.

Various containers can be used to start seeds. Options include reused things like egg cartons and cut-up half-and-half containers, biodegradable peat pots, expandable peat pellets, and the plastic cell packs in which transplants are often sold. Containers with 1.5-inch-wide cells are appropriate for most vegetables.

Regardless of the type of container you use, be sure it is clean and has adequate drainage holes. If you reuse cell packs, clean them and then sanitize using a 10 percent bleach solution or other product labeled for this purpose.

Germination or seed-starting media typically contain fine particles of peat moss and perlite. Use sterile media to avoid problems with diseases and other pests. Water it well before planting seeds.

Vegetables have different optimum temperatures for seed germination and growth. Temperatures between 70 and 75 degrees F during the day and about 65 degrees F at night are good for most warm-season vegetables. “Seedless” (triploid) watermelons are an exception. For these, the temperature should not get below 70 degrees F, and temperatures between 85 and 90 degrees F are recommended.

If you have a home greenhouse, make sure to ventilate it adequately during the day so that transplants don’t get excessively hot. This can happen even in winter.

Plants need adequate light. To grow transplants inside a house or apartment without grow lights, you’ll need a spot with very bright light coming through the window.

Seedlings also need an adequate but not excessive amount of water. Lifting transplant containers is often helpful when determining if they need water or not. When they feel lightweight, they likely need to be watered.

Use of a water-soluble 20-20-20 fertilizer, beginning when seedlings have their first true leaves, is often recommended. These fertilizers can be ordered. Alternatively, a half-and-half (1:1) mixture of the 24-8-16 and 15-30-15 water-soluble fertilizers commonly found in stores would produce a 20-19-16 fertilizer, which would probably be satisfactory. A dilute mixture of such fertilizer (approximately 1 teaspoon per gallon of water) could be applied once per week, or an even more dilute mixture (1 teaspoon in 5 gallons of water) could be used each time they’re watered.

When you get close to the time you plan to plant in the garden, take steps to harden off transplants.

While you prepare for your spring garden, keep in mind that you still have time to plant many cool-season vegetables. We can garden year-round in Louisiana.

Let me know if you have questions.

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Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).