Grow your own vegetable transplants

Story and Photos by Bob Westerfield

When it comes to the summer garden, most folks purchase their tomatoes, peppers, and other vegetables as transplants from a garden center. While it is relatively easy to start some vegetables by direct seeding into the garden soil, others are more temperamental and normally started as finished transplants. 

Undoubtedly, if you have purchased any transplants in the Southeast, they likely came from Bonnie’s Plant Farm. Bonnie’s basically has a monopoly on the market and keeps most garden centers and nurseries in the Southeast – as well as other parts of the United States – stocked with healthy transplants. 

This young lettuce transplant is being planted in a raised-bed garden.

This is for good reason. Bonnie’s does an excellent job of growing healthy, stocky, vegetable transplants that are ready to be planted in the home garden. If your goal is to only plant a couple of tomato, pepper, or other vegetable plants, it certainly makes sense to buy your transplants locally. On the other hand, if your goal is to plant several rows of tomatoes, broccoli, or Brussel sprouts, you should consider growing your own. 

With the rising costs of transplants at the garden centers and sometimes limited availability of desired cultivars, growing your own transplants makes a lot of sense.

Transplants are not difficult to grow and you’ll save money when planting large amounts. In addition, by growing your own transplants, you can select what varieties you want to plant and will not have to rely on what the garden centers offer. By following a few basic steps, you can have transplants ready for this fall garden or next year’s spring crop. 

Perhaps the first item of discussion should be the growing medium. In most cases, it is best to select a soilless medium that is intended as a germination mix. These mixes are normally light and airy, allowing seeds to germinate and root out easily, while providing superior drainage. Garden centers, as well as greenhouse supply companies, sell different types of germinating mixes. I buy my growing mixes from a place called Griffin Greenhouse in north Georgia. Do not make the mistake of using potting soil, or worse yet, raw garden soil, to germinate your seeds. Most potting soils are too heavy and garden soil can be full of diseases that can hamper germination and growth. 

Young tomato plants off to a good start growing in a hobby greenhouse.

You will also need some type of containers. These are also available from greenhouse supply companies, but you should be able to find them in the back of most vegetable seed catalogs. There are many different styles and sizes of growing containers out there. Some folks like to start their seeds in one big tray and transplant them to larger containers after they germinate and develop. I prefer to direct seed into 3-4-inch pots that are approximately 3 inches deep so that I do not have to take the additional step of shifting them up to a larger container. These little pots fit into a slotted tray that holds anywhere from 15 to 20 containers at a time. When we seed our vegetables, we fill the pots up just shy of the top of the container. We then carefully sprinkle two to three seeds per cell to ensure that at least one germinates. We take a small handful of soil and put ¼ inch or so over the top of the seeds. Lastly, we use the back of an empty container to lightly tamp the soil to firm up the seedbed, making sure there is good soil-seed contact. 

Temperature and light are the next major considerations. Most seeds require a tremendous amount of light to germinate and grow into healthy transplants. When it comes to light, there is no substitute for actual sunlight. A small-frame hobby greenhouse or south-facing sunroom might be the best locations for growing your transplants. If you don’t have areas like these, you can successfully grow them under artificial light. The best artificial light comes from growers’ lights that can be found in the back of seed catalogs. These lights emit a broad spectrum of light waves that are conducive to good plant growth. In the absence of a true grow light, you can use an adjustable hanging shop lamp with 3-4-foot-long soft fluorescent bulbs. With any type of artificial light, you must adjust it so that it’s within 1 inch of the soil before germination. After germination, when true leaves have formed, begin to slowly raise your light a few inches. The trick is to keep it close enough without burning the foliage. Plants benefit from 12 to 14 hours of artificial light per day in the absence of sunlight. Germinating seeds also need temperatures between 65 and 75 F. If you are growing outdoors in a cold frame, you may need to run some type of heating lamp or use a germinating heating pad that goes underneath your containers. 

Another requirement for successfully growing transplants is providing ample water and fertility. Soluble liquid fertilizers are usually the easiest way to provide the nutrition your developing transplants need. A balanced liquid formulation of 20-20-20 should carry your transplants all the way to completion. Fertilize at planting time and then approximately once a week throughout the life of the transplant. Transplants typically take five to seven weeks to develop, depending on the vegetable. While you only fertilize on occasion, irrigation will need to be on a daily basis. Depending on the soil and temperature, you may need to lightly irrigate once or twice a day. Take care to water gently so that you do not disturb the seeds. Some type of fine misting head would be ideal for watering transplants. If your transplants suddenly start wilting or a green, crusty soil appears in the top of the container, you may be keeping the soil too wet. Make adjustments to improve the situation. 

These basil plants are fully rooted and ready to go to the field.

While growing transplants is not difficult, you do need to keep your eye on them for any invading greenhouse pests or diseases. If your transplants seem too tall and spindly, it is either because they are not receiving adequate light or they are too crowded. One trick to try if your transplants seem spindly is to gently agitate them by taking a magazine or a piece of cardboard and slowly wave it back and forth, causing the stems to move, but not dislodge. Doing this approximately 30 seconds once or twice a day actually causes a beneficial stress to the plants that will trigger them to thicken up their stems. 

With the rising costs of transplants at the garden centers and sometimes limited availability of desired cultivars, growing your own transplants makes a lot of sense. It does not require a lot of sophisticated equipment to get the job done. I have even seen transplants grown in containers as simple as egg cartons or small drink cups. By paying attention to the few important details, you can start growing your own transplants and adding a new level of enjoyment to gardening.

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