How to Start Vegetable Seeds in a Greenhouse


Having a greenhouse to start your vegetable seeds is a true advantage, especially if you experience relatively cold winters. The greenhouse allows you to get a head start on growing your vegetable transplants before warm weather sets in. Once the warm weather of spring arrives, the vegetable transplants will be ready for their new home outside in the garden. Growing in a greenhouse can be a little more work as you are in total control of how much water, heat or nutrients the vegetable transplants receive. Starting your vegetable seeds in the greenhouse is relatively basic that even a novice gardener will experience success.

Step 1

Consider the vegetable plants you intend to grow and how many plants are required to fulfill your family's needs. Plants such as tomatoes, peppers, herbs, eggplants, broccoli and cauliflower are tolerant to transplanting. Sow your root vegetables, such as radishes, carrots, beats and parsnips, directly into the ground as they do not tolerate transplanting. Beans, peas and corn do not transplant well.

Step 2

Calculate the expected planting date with the germination period and when its appropriate to transplant the particular vegetable into the ground. Seed packages usually have this information listed on them. Vegetables such as cucumbers and melons germinate in approximately four days and are ready for transplanting in three to four weeks. Eggplants and tomatoes germinate in approximately seven days and transplanted in five to eight weeks, while peppers and onions germinate in seven to 20 days and transplanted in 11 to 16 weeks.

Step 3

Select small containers or a seed-starting tray to plant your vegetables seeds. If using plastic containers, make sure they have drain holes in them. Some seed starting containers are made of biodegradable materials, allowing you to plant the container and seedling directly into the garden without disrupting the root system.

Step 4

Fill the seed-starting container with a well-draining potting mix, rich in organic matter. Select a potting medium that drains well and does not retain water, or your vegetable seeds will rot before germinating.

Step 5

Plant the seeds to their specified depth. If planting in a seed-starting tray, space the seeds in the tray according to the specified spacing on the package.Mark the vegetables with plant marking stakes, if planting more than one variety.

Step 6

Water the seeds until the soil medium is thoroughly moist. Keep the seeds moist during the germination process. Do not saturate the soil.

Step 7

Place the seed containers or trays on a bottom-heating mat to keep them warm or allow the temperature inside of the greenhouse to maintain 70 degrees F during the germination process. Once the seeds have sprouted, keep the nightly temperatures in the 50s or 60s degrees F.

Step 8

Fertilize the seedlings after approximately three weeks with a water-soluble, liquid fertilizer, applied at half strength. Continue to fertilize weekly.

Step 9

Transplant the vegetable seedlings into the garden once they have established themselves in their original container and are ready for living outdoors in the ground.

Things You'll Need

  • Containers
  • Seed-starting tray
  • Potting mix
  • Plant labels
  • Water-soluble fertilizer


  • Greenhouse Gardener's Companion: Scheduling in the Greenhouse--Get Ready for Spring Seeding
  • The Vegetable Garden: Planting Schedules
  • Planting Vegetables from Seed and Seedlings
Keywords: growing greenhouse vegetables, starting vegetables greenhouse, vegetable seeds greenhouse

About this Author

Joyce Starr is a freelance writer from Florida and owns a landscaping company and garden center. She has published articles about camping in Florida, lawncare, gardening and writes for a local gardening newsletter. She shares her love and knowledge of the outdoors and nature through her writing.