We’re smack dab in the middle of the seed starting season, or maybe just getting ready to start in more northern climes. It seems like a good time to review some tips for germinating seeds and growing seedlings indoors ahead of outdoor planting. And while the basics of seed starting are pretty simple, there are always some tried-and-true tricks as well as some timely reminders to make your seed starting experience a worthwhile one. First time seed starter or someone who just wants to review the basics? Try here.
Most Important: The one thing we’ve found to be most important among many important things when starting seeds indoors? Moisture control. This means not only controlling the moisture in your starting mix, but providing the proper drainage. And, in the circular, everything-is-related-to-everything-else world of gardening, this means using the right starting mix.
#1 SEEDLING MIX
Increase germination success with garden supplies from Planet Natural. We carry all the flats and trays, potting soils and starter plugs you need to make seed starting a snap, as well as heat mats to provide optimal temperatures, and grow lights to keep `em growing strong!
Of course you can buy a good, organic starting mix. We don’t like to use potting soil mixes unless we blend in some of the ingredients — like perlite, charcoal, or coconut coir (we prefer using coir because, unlike peat moss, it’s a renewable resource) — that facilitates good drainage. You can also make your own starting mix. There are several good recipes that involve leaf mold, compost, garden soil, sand, and other drainage facilitators. We usually avoid garden soil. It has a tendency to compact (bad drainage) and may harbor diseases. Of course you can sterilize the soil before you use it, but that will also kill the beneficial microbes and other organisms that will help your plants get off to a good start. And it might make for kitchen smells your family isn’t used to.
Best is to make your starting mix with your own compost. A good quality compost — be sure to screen it first — helps with drainage and only gets better as you add other drainage inducing ingredients. Some recipes suggest equal parts compost, vermiculite/perlite, and coir or sphagnum moss, but we like to up the compost ante to three and even four parts compost to one of drainage material. Here’s a simple recipe that’s easy to make. Using compost has the advantage of not having to use fertilizer in a seedling’s early, tender stages when they’re particularly sensitive to burn. And because compost is usually well-balanced, you don’t have to worry about too much nitrogen keeping certain seeds, such as lettuce, from germinating.
Another component of good drainage is the container used to start your seeds. An acquaintance recently remarked about starting seeds in egg cartons, one seed per egg spot. Not only does this make for bad moisture control conditions, it also doesn’t allow proper room for root growth. Make sure your seedling have enough space, both in depth and between plants, for good growth. And make sure your containers have holes in the bottom for drainage. If you’re starting something that will be in its container for a while, say tomatoes (though they’re easy to transplant), you might even want to put some broken pottery shards or pea-sized gravel at the bottom of the container to make a place for extra moisture to drain through.
Once your seeds are planted, covering the flat or container with plastic wrap will help control moisture levels until seedling appear. But don’t overwater!
It’s important to know how far in advance to start your seeds ahead of the date they’ll go out into the garden. The best way to do this is to keep records from year to year. Sure, there are charts that can give you guidance — here’s one designed for zones 5 and 6, with suggestions on how to convert for warmer and cooler zones. Record not only when you start seeds indoors but the dates of last frost and when plants were hardened off and set out. You’ll be glad you did. And don’t forget to label starting pots and flats as to which seeds they contain. Those little seedling will often look a lot alike and you might not be able to identify them until it’s too late.
All heirloom seeds offered by Planet Natural are non-treated and non-GMO.View all
All heirloom garden seeds — not the sort you’ll find in box stores — offered by Planet Natural are non-treated, non-GMO and NOT purchased from Monsanto-owned Seminis. Planting instructions are included with each packet and shipping is FREE! Need advice? Visit our vegetable guides for tips and information on growing specific types.
Once your seedlings emerge they need light. We’ve found that a window sill, even a sun porch, doesn’t provide enough light to grow strong, healthy, compact starts. Use some form of artificial lighting– we especially favor the T5 fluorescent bulbs for the quality of their light, the simplicity in using them, and relative low expense to purchase and operate. Once seedling emerge bring the light as close to the plants as possible. Keep a close eye on growth and move the lights up as they progress. We give our starts 12 hours of light a day.
Seeds need warmth to germinate. That’s why we’ve always recommended a heating mat. But a young, grade-school friend of ours once recommended that we put our overflow tray on top of the refrigerator. He’d been studying energy usage and had discovered that the energy used to cool a refrigerator made for warmer temperatures on his top. It worked! It’s also a good place to let bread dough rise during the cold days of winter.
Once seedling our up and growing, don’t be afraid to touch them. A gentle brushing across the top will result in sturdier stems and hardier plants.
More tips on seed starting. Here you go. And here you go again (PDF). Have any tricks, suggestions, or special techniques when starting seeds indoors? Please share them with us and our followers. We’d like to know!
T5 Grow Light (2 ft)
Delivers performance and high lumen output from multiple hanging positions.
Create your own 2 in. biodegradable plant starters out of recycled newspaper.
Improves planting success by creating the perfect growing conditions -- indoors!
Winner of several gardening awards, CowPots are made by American dairy farmers.