Starting Seeds: 5 Secrets to Great Greenhouse Results
why you should start your seeds indoors
Starting your seeds in a seed tray indoors or in a greenhouse will make it easier to keep them moist while they germinate. If you don't keep them moist out in the field, there's a good chance they won't germinate evenly. Starting your seeds indoors also allows you to use a lot less seed. When we sow directly in the field, we always use extra seed in case of poor germination. Beans, melons, and cucumbers aren't suited to transplanting, however, and should be sown directly in the garden. Other crops, like carrots and beets, are planted too close together to transplant well. It would be too tedious, so we sow those directly as well.
1. Prepare your growing medium
We fill our seeding trays with a mix of compost and peat moss. The peat moss helps to retain water. We used to just use compost, but we found that the water retention of peat moss gave us a much better result. It also seems to allow the roots to develop better so that when we transplant, the entire root system pulls out of the tray without breaking apart. You can purchase peat moss at Home Depot. You can get compost locally, make your own, or try Vermont Compost.
2. Set up Your Planting Table
It's worth it to set up a planting table so you can stand and do your work, and that way the plants can have a place to live while they wait to go in the garden. We use cement block, posts or 2 x 4's, and strips of plywood or pallets. You can also use thick wire mesh, but then you'll need to make a frame to support it. We love pallets because they are sturdy but not solid. We want the water to drain out. If water collects under the seed trays, you'll end up with plant roots coming out of the bottom of your tray and attaching to the wet wood underneath.
3. Fill your trays with growing medium
Use an old yogurt container or a trowel to fill the trays with soil mix. Don't pack it too tightly. The roots need space to develop. Leave room at the top for more compost after you plant the seeds. Water thoroughly before you plant. You want the surface to look shiny for a few seconds. It will take much longer than you think to completely moisten the growing medium. Poke your finger into the soil to see if its moist all the way through.
4. Plant your seeds in the trays
Use your fingers to tamp the soil in each cell and make a little divot. Place one seed in each hole. If you're using poor quality seed plant two seeds and thin later. Sprinkle some more growing medium on top.
5. Keep the seed trays moist.
We use big styrofoam trays that are stackable. By stacking them, you won't have to water them until they germinate and you unstack them. If you do stack them, be sure to check for germination every single day, and unstack the trays that have even one seed that has germinated. You can leave your trays in the shade until they form their first true leaves. They are unable to process sunlight before then, and it will cut down on your watering. I water my trays once a day, in the morning. If they look dry in the afternoon, always give them more water. Once they have their first true leaves they need partial shade. Too much shade will leave you with long, leggy, thin-stemmed plants, while too much sun could kill them if you forget to water (it happens!)
6. Mark your calendar
Write down what you planted and when in a spreadsheet or calendar. Make a new entry on the date three weeks from now, and write a reminder to plant that again. If you plant every three weeks you'll always be harvesting! It's also helpful to write down the date you planted so that if something doesn't germinate after 2 weeks, you'll know to resow.