How to Plant Seeds in a Greenhouse


A wonderful way to control your growing environment--and plant year-round--is to plant seeds in a greenhouse. Whether you're interested in growing a flower garden, planting fruits or vegetables, or giving a good start to a future houseplant, starting from seed can require daily attention, but not much actual work. With well-grown, strong seedlings you'll be more likely to grow thriving, strong plants that can show off beautiful flowers or produce healthy foods for your family to enjoy.

Step 1

Place your seed tray on a flat level surface, such as a table or bench in your greenhouse. Set up your pots in the tray with the bottoms of the pots touching the base of the tray, not tipped against one another.

Step 2

Fill each pot with soil almost completely to the top. Plant your seeds to the correct depth depending on the types of plants you are going to grow and package recommendations. Cover the seeds, when required, but avoid pressing the soil down over them.

Step 3

Add an inch of water to your seed tray and allow the pots to soak up the water. You'll notice the top layer of soil turning darker as the soil becomes moist throughout the pot. Add 1/2-inch increments of water as needed until all of the pots are moist.

Step 4

Set your seed tray lid over the tray or wrap a piece of plastic wrap over the tray. This will help hold in the moisture for the seeds rather than letting it evaporate freely into the greenhouse air.

Step 5

Add more water as needed to the tray when you notice the top layer of the soil drying out. While the pots should never sit in standing water for more than an hour, do not let your pots go completely dry or the seedlings may not be able to recover.

Step 6

Remove the lid or plastic wrap from the tray when the seedlings reach the ceiling and all have germinated. If some seeds need more time than others, remove the tall, growing plants from the tray and leave the pots which are taking longer in the tray with the lid.

Step 7

Transplant the seedlings after a few months to a container to stay in the greenhouse, or plant outdoors into a garden during your growing season with no fear of frost at night. If your plants are going outdoors, be sure to harden them off for about a week to get them conditioned to outside wind and temperature fluctuations.

Things You'll Need

  • Pots
  • Seed tray
  • Tray lid or plastic wrap
  • Potting soil or seed starter
  • Seeds in packet
  • Water


  • Success with Seeds; Chris Wheeler and Valerie Wheeler; 2004
  • Growing Fruit and Vegetables; Richard Bird; 2003
Keywords: planting seeds, starting seeds in a greenhouse, how to plant seeds in a greenhouse

About this Author

Writing from Virginia, Margaret Telsch-Williams specializes in personal finance, money management, gardening, crafts and sewing, cooking, DIY projects and travel. When not writing instructional articles online, she works for the website Widescreen Warrior as a contributor and podcast co-host discussing all things film and entertainment. She holds a Bachelor of Science in biology and a master's degree in writing.