This is the first of a three-part post about starting seeds indoors. If you’ve never done it before, the main thing you should know is that it’s really easy.
Seeds are little stored bundles of energy that are just waiting to sprout, and once planted it’s hard to hold them back. By observing just a few general guidelines, you’ll have excellent success with your own seed starting enterprise.
First of all, this is how I start seeds; many readers will have other methods they prefer. As I say, seeds are pretty adaptable to different ways of getting them started. This blog is about sharing ideas, so I’d love to hear your tips for starting seeds in the comments below.
Before you begin, you need a place to start your seeds. Some people use a sunny window, and others start seeds in less light but in a warm location, like on top of a refrigerator. I start all of my seeds under lights at the MSHS office. Years ago someone donated a sort of mini-greenhouse to our organization, and that’s what I use to start many things. It consists of a fluorescent light suspended by a height-adjustable bar, and is covered by a removable vinyl hood that both reflects light and raises the temperature a little bit inside when it’s pulled down.
There are lots of different portable grow-light setups you can buy, and you can find them at most any place that sells seed-starting supplies. All you really need though are basic two-tube fluorescent shop light fixtures, which are pretty inexpensive. For other seed-starting setups in the office, I take plastic Rubbermaid shelving units about 5 feet tall and suspend shop lights from the bottom of each shelf with different length bungee cords. That way I can raise the lights as the seedlings grow.
I sometimes use electric heating mats made for seed starting under my growing trays to obtain faster germination, but they aren’t really necessary in a normal household room temperature environment. They’re particularly useful if you’re growing seedlings in a cooler space, like a basement. Moreover, if you start seeds inside an enclosed space like my mini-greenhouse, I’ve found that they can actually raise the temperature too high and quickly dry out the soil.
Once you have a place to start seeds, it’s time to get something growing. Start out by reading the seed packs of the vegetables you plan to grow. They are usually sources of good information, including when you should start a particular variety relative to the last average frost date for your area. For most things, that’s eight weeks before the last frost date, but those who are planning to grow slow-to-develop varieties like leeks will be advised to start them much earlier.
I always begin with lettuces and leafy greens, because although they are quick to sprout and grow, they appreciate cooler temperatures and I can move them outside into a cold frame earlier than other vegetables.
Clear plastic food containers with lids make great containers for starting seeds; I save them throughout the year and ask friends and coworkers to do the same for me. Most any size or shape will do, though deeper is better. I take the clean containers and drill several holes in the bottom for drainage. Then I fill a dishpan with potting soil, place it in a sink, and slowly start running the water to wet the mixture, lightly kneading until it’s thoroughly mixed and pliable. You want it to be evenly moist, but not sopping wet.
Then I fill the growing container about ¾ full of mix, and smooth the surface of the soil until it’s even. If I’m starting lettuce seeds I put on about an inch-thick layer of moistened seed starting mix, which is a finer consistency than regular potting soil and better for tiny seeds like lettuce.
After that I’m ready for the seeds, and here’s where planting depth comes in. It’s important to read the recommended depth on the seed pack, but in general, the smaller the seeds, the less soil cover they need. Lettuce seeds prefer a minimal planting depth. I pinch some between two fingers and gently sprinkle them over the planting surface, trying to distribute them as evenly as possible, and approximately a half-inch apart. After the entire surface of the container is covered with seeds, I lay down a very fine layer of more seed starting mix on top, about 1/8 to 1/4 inch at most, and mist the surface with a spray bottle.
The lid then goes on, elevating the temperature inside and trapping condensation and humidity to promote germination. I position the light just a couple of inches above the top of the container, moving it up as the seedlings grow. I usually leave the lights on all the time until the seeds germinate, and then 12 to 16 hours a day after that. Within a couple of days for lettuce, sprouts begin to appear, and when most all of the seeds have germinated I remove the lid and check the soil for moisture, watering lightly or misting if needed.
Follow Notes from Northern Gardener throughout January as we offer our series on 31 Days to a Great Northern Vegetable Garden. Tomorrow: Starting Seeds Indoors, part 2: Starting Seeds in Peat Pots.