Starting From Seed

Jim Seymour
Carroll County Master Gardener

There is nothing quite like sticking a seed into a container and waiting until that brown surface shows its first leaf. Man, that's satisfaction. Some folks would rather grow their own vegetables from a favorite variety and others just want to grow stock plants rather than buy them at the garden centers. But, whatever the reasons there are some important points that will insure a successful effort.

First, is the container. They are available from garden centers, nurseries or mail order. There are all types and the choice is a matter of preference. Container types include peat pots, peat pellets, fiber blocks, plastic pots and trays a cell flats. Whatever container you choose, it must provide drainage of excess water from the bottom to keep the soil or potting mix from staying too wet.

Since the volume of medium available to roots will determine the size to which a transplant can grow, select a container size appropriate for the size of plant you want to produce.

Seeds of slowly growing plants, such as tomatoes, pepper, cabbage and broccoli, can be planted in a small tray and the plants moved to a larger container once they have started to develop one or two true leaves.

Seeds of rapidly growing plants such as cucumber, muskmelon, squash, pumpkin and watermelon, should be planted directly into a container large enough for mature transplants. Be sure the root system of the seedling surrounds and holds the medium together before the seeds are transplanted. Vine crop seedlings are especially sensitive to root damage at transplanting.

The media you select to grow in makes a difference and should be given careful consideration. Soilless growing media usually produce better transplants than mineral soils. Soil is often contaminated with weed seeds, nematodes, fungi and bacteria that may cause plant losses. Heavy soils such as clay drain poorly and keep the seedlings to wet.

Commercial soil-less mixes are made of pet moss, vermiculite, pine bark and other organic materials. They usually contain some added nutrients, are free of pests, and have good drainage and water-holding properties. If using pure vermiculite for starting your plants, you should realize its fertility is low and plants will be stunted unless they are replanted soon after emergence. If plants begin to develop a yellowish color, it may be necessary to use a small amount of soluble fertilizer. Water transplants with a fertilizer solution containing 2-3 teaspoons per gallon of a soluble 20-20-20, 15-30-15 or similar soluble fertilizers. Always follow the manufacturer's recommendation, this is printed on the container.

Another critical factor, when growing seedlings is the amount and source of light. Seedlings will not need light until they emerge from the medium. Once they appear, transplants will grow better if they receive at least six hours of direct sunlight each day. Hotbeds, cold frames and small greenhouses are thus your best bets. Windowsills or basements in most homes don't offer sufficient light and plants will be small and spindly.

Artificial light can be provided by placing 40-watt fluorescent tubes six to 8 inches above the tops of the seedlings as they grow. Artificial light in combination with some window light will give better results. The light should be turned off at night.

Temperature is another important consideration. Seeds of cool-season crops will germinate at temperatures of 45 degrees to 80 degrees, while warm-season vegetables will germinate at 70 degrees to 90 degrees. Germination will be most rapid in the top 10 degrees of these ranges.

After germination occurs, cool-season crops should be grown at 60 to 70 degrees during the day and 50 degrees at night.Warm-season crops do best at day temperatures of 70 to 75 degrees and 60 degrees at night.

Remember that seeds and plants will need an adequate amount of moisture for germination and growth. Avoid over watering, however, some root development will be poor and diseases are most likely to develop if the growing medium is kept saturated. Water only when needed, but don't let the plants wilt if you can avoid it.

Damping off is probably the most common disease of young seedlings. It is caused by several types of fungi that attack the stem at or near the soil level. This causes a collapse of the stem, and the seedling falls over and dies. Use soil-less growing medium and careful watering to allow the surface of the medium to dry between watering will help reduce damping off problems.

Reduction of temperatures and moisture or exposure to outdoor conditions for seven to 10 days prior to transplanting will help plants to acclimate to outdoor conditions. This process is referred to as hardening vegetable transplants.

The time required to grow transplants to desired sizes will vary with the type of vegetable, the temperature, and the amount and quality of light. The following are approximate times required for planting seeds until transplants are ready to be planted into a garden:

  • 2-3 weeks: cucumbers, muskmelon, pumpkin, squash, and watermelon.
  • 5-7 weeks: tomato, head lettuce, broccoli, cabbage, cauliflower, brussel sprouts
  • 6-8 weeks: eggplant, pepper.

Some final suggestions: Do not allow transplants to become too large, especially if they are grown in small containers. Tomato and pepper transplants should be about six to 8 inches tall. Cucumbers, squash, and related vine crops should be planted when the second true leaf is expanding. If plants are small, remove any flowers or fruit from plants prior to transplanting.

On your mark....Get set.....GROW!

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