Columns, In the Garden

Get Ready to Start Seedlings Indoors

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Metal planting cells from Gardeners Supply.

by Henry Homeyer

CORNISH FLAT, N.H. – Starting seeds indoors under lights is a good treatment for the winter blues. It connects me to my upcoming garden and all its benefits. Early March is when I start onions and peppers, though April is the month for most everything else.

My wife, Cindy Heath, and I are making a commitment to reduce and eliminate the use of plastics in our life, so we are transitioning away from those handy, dandy flimsy plastic six-packs for starting seeds. You can, too.

Gardeners Supply Company has been offering ways of reducing single-use plastics like those six-packs sold everywhere. They have sturdy reusable plastic trays for seed starting which have been available for a few years. This year they came out with metal seed starting trays.

These galvanized steel growing cells are pricey, but should last a lifetime. For about $50 you get 24 individual, tapered cells and a leak-proof tray to hold them. The cells are a nice big size. The kit is self-watering: it comes with a wire grid and moisture-retaining mat that keeps seedlings hydrated from the bottom of the tray which you fill with water once a week or so. I got one of these kits and looks like a winner.

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Making soil blocks with a simple press.

Renee’s Garden is now selling seed starting cell trays made of silicone that are sturdy and reusable, and dishwasher safe. They do not get brittle, they say. I am ordering some to try them.

If you don’t mind extra work and lots of mess, you can make soil blocks using a little metal press that produces two-inch soil blocks. The mixture includes peat humus, compost, soil, blood meal and minerals. E-mail me for more info about the process.

So what else do you need? Lights, growing medium and seeds. Let’s start with lights. To keep your light bill low, I recommend using LED lights. I have some old-fashioned four-foot fluorescent lights, but have been replacing them with the LED equivalent. These look about the same, but have no ballast (transformer) inside the fixture and use much less electricity.

If you replace your old fixtures, don’t just throw the old tubes into the trash as they contain mercury, which is toxic waste. Some recycling centers will accept them, or bring them to an electrical supply company for proper disposal. And if you want to use an LED tube in an old fluorescent fixture, you should remove the ballast. Unless it says “No PCB’s on it, it needs to be sent to a hazardous waste collection site also.

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Plastic caps keep seeds from drying out.

Hang your fixture about six inches over the planting trays. Use jack chain, a small-link chain sold at hardware stores. It allows you to raise the lights as your plants grow. Give your seedlings 12 to 14 hours of light per day: they need a good night’s sleep as much as you do.

Most seeds will wake up and grow more readily if you place them on a warm base. Electrical seed-starting mats are great for that, but not really necessary. I use them for things that specify warmer temperatures, like the flower Lisianthus, and for hot peppers.

I recommend buying seed starting mix instead of potting soil to put in your planting cells. Why? Seed starting mix is a finer blend and works better. It is made from peat moss, vermiculite, perlite and fertilizer. You can make your own, of course, and I often do. I start 10 flats (trays) or more each year. I also mix in some high quality compost, about 50% of the final product. I also add a little Pro-Gro, a slow-release organic bagged fertilizer.

Peat moss is coming under criticism now by the eco-minded community. It is harvested from bogs and is centuries in the making. Coir, a palm fiber, is becoming more available, but I haven’t found it yet in big bags like peat moss.

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The Stella Natura calendar
gives planting times based on celestial rhythms.

Moisture is key for starting seeds. If the soil mix dries out before they get well established, they can quickly perish. That’s okay with me. I need a reason to get out of bed on gray days in mud season. Gotta check my seedlings and give ‘em a drink after I have my coffee!

You can contain moisture by buying and using clear plastic covers for your flats of seedlings. They are inexpensive and reusable. Take them off after everything has germinated, or most things.

A biodynamic calendar called Stella Natura is available for gardeners who want to plant seeds by the phase of the moon, stars and planets. I consult it when planting, and although not foolproof, I think it helps. Available at

So if you want another hobby, grow your own plants from seed. It takes a little practice, but it may make you happy. It works for me!

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