by Mark Levisay
In spite of the snow we’ve had recently this is a good time to think about starting garden seeds indoors. You may have a favorite variety of a vegetable or flower you can’t normally find at a garden center and planting them from seed may be your only option. Generally you can get a wider range of varieties of plants available in seed form, so learning to start them indoors is a good idea. It may take anywhere from six to eight weeks for the seedlings to be ready to harden off (more on that later) and germinating time might be up to two weeks, though many are much faster. Now is the time to plant seeds for plants you want ready for the garden in early April-things like broccoli and cabbage. Peppers and tomatoes can wait until March.
There aren’t too many things you’ll need to start seeds indoors, but good lights are probably the most important. Few homes have large south facing windows which might provide enough natural light for seed germination and growth. Better to invest in bright artificial light that you can place anywhere that you have space for a table. Today LED lights are probably your best bet, as they are lightweight, bright, use little electricity and last a long time. They usually are available in daylight spectrum light which is optimal for plant growth. In my last blog I detailed making my new three fixture LED which is 4’ long and can cover four “flats” of plants. If you don’t have that much room a 2’ long fixture would cover one flat and that might be all you need. You’ll want to hang them about 6-9” above the soil level of the pots you’re using and then be able to raise them as your plants grow.
You can use any kind of tray or pot for starting seeds as long as it has drainage and has been disinfected. You shouldn’t have to clean newly bought pots, but if your pots have been used before clean them thoroughly with a mixture of 1 part bleach to 10 parts water and let dry before filling with soil.
Two types of plastic “6-packs” used for seed starting. The larger fit 6 to a flat, where the smaller go 12 to a flat.
Currently I’m using the larger sized cups for plants that will be under the lights for quite a while. Later on I’ll use the smaller cups for things like tomatoes and peppers that will germinate and go outside pretty quickly. I also use a large flat tray under my plant flats to keep excess water from pouring onto the floor. This tray actually came from under the air handler in my heat pump system. This had cracked and needed to be replaced. I rescued and re-purposed it for plant duties. Any other flat, rimmed tray will work, or even an old towel placed on your table under the flats.
The soil you use in your plant pots is important—you don’t want it to contain any real nutrients for the plants and most general potting soils contain slow release fertilizer. Instead, use seed starter potting soil specifically designed for the job. Espoma, Jiffy, and Miracle Gro all sell these. I’ve had trouble wetting the Jiffy Mix thoroughly, so I usually use the Miracle Gro Seed Starter mix. Espoma is a good option if you are looking for an organic product. If you do buy the Jiffy Mix, put it in a bucket and soak it in water until it is thoroughly wet. Squeeze out the excess water before filling your pots. Never let the soil dry out, as it can be hard to re-wet, and seeds need constant moisture to germinate. You won’t need to add fertilizer until after the seedlings get their first set of adult leaves, and at that point you can use a liquid soluble general purpose fertilizer when you water.
Labels are really important, especially if you’re growing several varieties of the same plant, as all of the seedlings will look the same, and it’s easy to get confused. Some of the plastic 6-packs will come with plastic labels, but you can also make your own. Popsicle sticks, tongue depressors or even strips of cardboard will do. If you re-use them from year to year it’s a good idea to disinfect them with your 10-1 bleach solution.
Now let’s go through the procedure I use to plant the seeds. First, I fill the cleaned 6-packs with seed starter soil, level to the tops.
6-packs filled with dry seed starter soil
My second step is to put the packs in the driveway and water them with a watering can to thoroughly soak the soil.
6-pack after watering
You’ll note that the watering process compacts the soil slightly in the cups, giving you space to add seeds.
Next I’ll bring those wet 6-packs back in the house and put them under the lights, which at this stage really help you see what you’re doing! I label the 6-packs, or even the rows within them, and then place seeds into the cups. I generally put 2 seeds in each cup, and later thin out one if both germinate. With some flowers I let 2 plants grow and then separate them when planting. Press the seeds down lightly so that they make good contact with the wet soil.
6-pack with labels and pepper seeds
Next, I’ll cover the seeds with a small amount of the seed starter mix and water it. Some seeds need light to germinate (for example coleus and statice) so check your seed packs for specific instructions. Seeds only need to be covered to about their own thickness, so this isn’t much soil and I use a spray bottle rather than a watering can, as the spray disturbs the seeds less.
6-pack with seeds covered, and spray bottle ready for the next step.
Now for the waiting, as some seeds can take up to two weeks to germinate. Keep them moist at all times. Some people cover the moist flats with “Saran” plastic wrap to hold in the moisture. Some seed trays will come with clear plastic covers used to keep in moisture. I just use my spray bottle multiple times each day to keep the soil moist. Once the seeds germinate you can switch back to watering in a more conventional manner. Use the light from dawn to dusk, but don’t run them 24 hours a day. Keep the trays in a warm but not hot area of your home. I keep my house at 68F and have never had a problem. I have also started to use an oscillating fan on the other side of the room to simulate nature’s breezes, as I think this makes the plant stems stronger.
My light table set up with a flat of planted and watered seeds.
Once the plants are up you may need to raise the lights so that you’re always 6-9” above the tops of the plants. When the plants have grown for a while, they’ll start to look more like the ones you might see on sale at The Corner Store. Now it’s time to “harden off” which is the process of acclimatizing the plants to the great outdoors. Place them outdoors in a shady area, and each day give them a few hours of sun, increasing the amount each day for a week or until they’re in full sun. Keep them well watered, as the little plants are not used to this outdoor stuff. If it looks like rain you may want to put them under cover, as often a heavy rain will knock over the young plants.
Give this a try, and before you know it the process will be second nature. If you have any questions please e-mail me at marklevisay@gmail.com. Good luck!