Amanda Sears is the horticulture agent for Madison County, Kentucky. She can be reached at

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The Self-Sufficient Gardener
by Amanda Ferguson Sears    

Developing Transplants from Seed is Easy in a Greenhouse Setting

There is something very satisfying about raising your own food. In order to be self-sufficient, it makes sense to raise your own transplants. In addition to watching the magic of seeds becoming plants, it also provides the opportunity to give you the vegetable and flower varieties you want when you want them. Instead of relying on others, who may just be growing the most popular varieties, you can think outside the box and choose seeds that suit your tastes.

When growing your own transplants, it is very important to control temperature, ventilation, light and moisture. Temperatures for warm-season crops should be between 65 and 80 F during the day, with nighttime temperatures of 60 to 65 F. On a clear, sunny day heat can build up quickly in a greenhouse, which means ventilation is crucial.


These fall tomatoes were started in the greenhouse at the beginning of July and transplanted in early August.

Transplants should be kept in the greenhouse until two weeks before being put into the field. At that time, they should be put outside to be hardened off.

Plant your seeds at the correct depth. The depth varies between different plants. Check your seed packet for this information.

The quality of light in your greenhouse is equally important. Light influences how quickly the plant grows. On overcast winter days it may be necessary to use supplemental light.

Do not overwater your seedlings. The soil should be kept moist but not soggy. Keeping transplants too moist can lead to seedling death, due to a disease known as “damping off.”

It is very important to start out with high quality seeds. If you are using seeds that you have saved from the last year’s crop, make sure they have come from disease-free stock. It may be wise to disinfect your seeds with a solution of 1 cup bleach to 3 cups of water and a few drops of dish detergent. Let them soak for one minute, then rinse with clean water and allow to dry. Start your seeds in a plant tray using a growing media of perlite and peat moss. Media of this sort can be purchased at any garden center.

Any type of tray with drain holes can be used. If you have saved your flats from previous years of buying transplants, these will work well, although they should be sterilized properly. Fill the trays but do not compact the media.

After the trays have been filled, create a “dibble.” A dibble is the technical term for an indentation in the cell of the tray where you plan to set your seed. The depth of the dibble depends on what you are planting. Plants in the cucurbit family (cucumbers and pumpkins) need to be planted 1 inch deep. Tomatoes should be planted 1/2-inch deep, while eggplant, pepper, cabbage, lettuce and cauliflower are 1/4-inch deep. Once a seed has been placed in the dibble hole, fill the dibble with media. After the seeds have been planted, water them until they are moist, but not soggy.

Fertilize your seedlings when the second set of true leaves appears. A liquid fertilizer, such as 20-20-20, is best. Just check the label for recommendations. Continue to fertilize once a week until you transplant.

Before the time comes to transplant your seedlings, you must first “harden off” your plants. This means acclimating them to the harsh weather of the outdoors before planting them. Growing your plants in the greenhouse has babied them and given them everything that they need; to harden off gets them ready for life in the real world. About two weeks before transplanting, reduce the moisture and amount of fertilizer that the plants are receiving. Move the plants to a location of lower temperature (not lower than 60 F) during the day, and back to their protected area at night.

When the time comes to transplant, it is important to realize that this can be a very traumatic event in the life of your plant. Growth may be temporarily slowed. To reduce this risk, handle carefully and do not disturb the roots. Transplant on a shady day or late in the day to avoid wilting. Make sure the hole is big enough so that you do not have to cram your plant in the space. Add 1 cup of starter fertilizer solution in the hole around the plant at the time of planting. You can use the 20-20-20 fertilizer that you used in the greenhouse in the field as well. Mix 2 tablespoons of fertilizer to 1 gallon of water. Water the transplanted seedlings once or twice over the course of the next week while they get used to their new surroundings.

Expand your green thumb and make yourself more self-sufficient. Growing your own transplants is a great way to ensure quality in your garden.


Several Choices for Transplant Containers

Many different items can be used as pots when starting transplants. Old flats that plants once came in are ideal, but items such as egg cartons or paper cups also work well. It is important to drill a hole in the bottom for good water drainage.

Another option is using peat pots, which are hard discs that expand when wet. No matter what type of pot you use, you should put them in a tray to make watering and transport easier.


(From Volume IV Issue VI of Kentucky Gardener. Photos by Amanda Ferguson Sears.)


Posted: 11/23/11   RSS | Print


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