I have to be honest, I do not grow my own transplants from seed. The small size of my garden does not justify the investment of the money, time and space needed for starting seeds indoors. However, there are several very good reasons to grow your own transplants. The main reason is that it allows you to grow transplants of varieties, such as heirlooms, that are not available at local garden centers.
Another justification for growing your own transplants is timing. You control when the transplants are ready for the garden. For example, cool season crop plants are often not readily available at garden centers early in the season when they should be planted. Expense is another factor in starting transplants at home. If you have a large garden, commercially produced transplants could be cost prohibitive. Whatever the reason for starting seed indoors, there are some common mistakes you will want to avoid.
▪ Not using a quality seed starting mixture: Seed starting mixes contain various ingredients, such as vermiculite, peat moss, coconut coir fiber, and perlite. These mixes are sterile, well-drained, lightweight, and a finer texture than regular potting soil mixtures. Regular potting soil mixtures tend to be heavier and stay moist longer. This can lead to a fungus problem, called “damping off,” that attacks and kills young seedlings. Avoid the loss of time and vegetable seeds, by using a good seed starting mix, either a commercially available mix or one you make yourself.
▪ Not providing adequate light: Before you even get started, assess your light situation. Too many gardeners assume that they can grow their transplants on windowsills, but the plants seldom get enough light even if the window faces south. Almost always, supplemental lighting is necessary for growing quality transplants at home. You do not need expensive “grow-light” bulbs to provide this extra light. The most inexpensive option is to make your own grow-light frame with a shop light fixture that has two 4-foot fluorescent 40-watt cool white bulbs. The frame should allow for adjusting the height of the fixture above the plants.
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Cornell University has a plan online for making one with inexpensive PVC pipe, or you can buy one either at a local indoor gardening store. A simple setup should cost less than $100. The investment is definitely worth it. Seedlings without adequate light grow poorly and have weak, spindly stems.
When using grow-lights, situate the fixture no more than 4 to 6 inches above the plants and raise it as the plants grow. Because the plants need a nighttime rest period, use a timer to turn the lights off for 8 to 12 hours every night.
▪ Planting seeds too early: At this time of year, gardeners with spring fever get anxious to start their seeds. Their rush to get seeds planted results in transplants that are ready long before it is time to set them out in the garden. Keep in mind that for our area, the average date of the last frost is in the first two weeks of May. While many gardeners aim for planting warm season crops outdoors on this date, it is often too early because soil and air temperatures are still too cool for the plants to thrive.
Check out the handy chart in WSU Extension Publication EM 057E “Home Vegetable Gardening in Washington” available at http://cru.cahe.wsu.edu/CEPublications/EM057E/EM057E.pdf . It indicates how many weeks it will take to grow different crops to transplant size after seeding.
If you have spring fever and plan to grow your own transplants, now IS the time to order seeds and get your supplies ready, but it is NOT time to plant yet.
Marianne C. Ophardt is a retired horticulturist for Washington State University Benton County Extension.