One week old tomato seedlings grow under lights in my office. While I planted 16 seeds per container, some didn’t sprout. There are, perhaps, 70 going strong. To the right are pepper seedlings barely visible under their shop light. That light is so much closer to the plants because I lifted the fixture above the tomatoes to fit the camera under it for the photograph.
Sprouts are up! One hundred and six sprouts grace my seed-starting shelf. Most are tomato plants though about 24 are pepper plants and another 8 are lettuce.
I live in USDA hardiness zone 6b or 7a, depending on how you squint at the most recent map. While it felt more like zone 3 this winter, the temperature might have just brushed minus 5 – the minimum low to qualify as zone 6b. What was unusual is the cold hung on day-after-day; we had a six-week period during which it was a relief if the temperature spiked into the low 20s.
Even as the snow melted, we had cold. There’s a popular rule of thumb in our neighborhood: plant peas on St Patrick’s Day. I doubt many people succeeded. In fact, cold and rain continued until just two days ago, so anyone trying to plant peas would have been working in mud. I don’t expect to put anything in the garden for another three or four days, assuming we don’t see even more rain.
How I Start Seeds
I recently attended my first seed swap where a presenter recommended that home growers buy celled seed-starting trays. I no longer go that route. I’ve used peat pots pressed out in connected cells, I’ve used compressed peat pellets, and I’ve used old plastic drinking cups. I wrote about much of this some years ago in evergreen blog posts.
Here’s a setup I created with my dad last spring. He found a seven foot section of wire shelving. We marked 17 inches in from each end of the shelving, cut the reinforcement wire along the front edge, and bent the two 17-inch ends down to create a stand from which to hang a shop light. My dad has a cabinet in his living room where he sets up trays and pots in which to start tree seeds. With chains to suspend the shop light, it’s easy to adjust the fixture’s height as seedlings grow tall.
These days I cut up gallon plastic milk and orange juice jugs and use the bottoms as seed planters. In a milk jug, I set 16 seeds, and in an orange juice jug, I set 12 seeds. Sure, roots grow together as the seedlings get large, but teasing (gently tearing) them apart doesn’t seem to bother them too much.
When I set seeds, I create a paper tag to identify which varieties of plants are in a particular container (and where the varieties are). These I tape to the side of the container for quick reference. I refer to the tags when I set seedlings in the garden and make a map that shows where I plant each variety.
The easiest thing to overlook when you start seeds indoors is lighting. Don’t assume a south-facing window can provide enough light to produce healthy seedlings. Instead, get a fluorescent fixture with 850K spectrum tubes (see the box titled Don’t Buy Grow Lights). When you first plant seeds, suspend the light about 3 inches over the surface of the soil. As seedlings grow, raise the light to maintain a 3-inch separation from the tops of the plants.
To start tomato and pepper seeds, keep the room temperature above 70 degrees. Ideally, shoot for 80 degrees which, if you don’t want to turn up the heat, you can achieve by putting a heating pad under the seed pots. I’ve found in a 70 degree room, fluorescent lights parked 3 inches above my planters warm the soil adequately.
Starting seeds indoors is only mildly challenging. If you have space to set up a light and some makeshift planters, don’t buy a flat of seedlings that someone else has started. You can grow that!
I start seeds in planters I create by cutting the bottom halves off of gallon plastic milk jugs. I start a cut by pinching the milk jug between the tips of a scissors and squeezing hard. If the carton proves too tough, I can poke a hole through with one scissors tip. Then I cut around the container on a line parallel to the bottom of the jug.
I buy a bale of potting soil every three or four years from a local garden center. A bale is an enormous amount of soil—compressed to about half its “fluffed” volume. To use it, I wield a butter knife as an ice pick, stabbing one end of the bale repeatedly until a chunk comes loose. I crumble the chunk into a planter and smoosh up smaller lumps between my thumb and fingers.
Note that I don’t put drainage holes in the bottoms of my homemade planters. This forces me to pay extra attention to the moisture of the soil. Before I plant, I add what must be about a third of a gallon of water and leave the planter for 30 minutes or longer so the water soaks in. The soil should be moist on the surface but there shouldn’t be water sloshing around in the container. Note your potting soil might float when you first add water. Worse: some potting soils don’t absorb water without encouragement. If you have such potting soil, stir the water in or it might just pool on top.
I use a chopstick to create 16 indents in the soil of a planter; orange circles in the photo represent the layout. For tomato and pepper seeds, these can be just one-eighth to one-quarter inch deep. I drop a single seed into each indentation and then gently nudge soil over the seeds. With all the seeds covered, I very gently tamp the soil down with the heel of my hand.
My labels aren’t pretty, but they work. This one reveals I have paste tomato seeds in the left two rows (for a total of 8), 3 Amana Orange tomato seeds at the back of the third row with one Tangerine Beefsteak seed in the front of that row, and a final full row of Tangerine Beefsteak seeds.
I may have to “pot up” the seedlings later which I do by gently tearing each one away from the root ball and then setting 8 into a milk-jug-derived planter. Of course, I create new labels for the new planters, and eventually I use those labels to inform a map I draw so I know where each variety ends up in the garden. I posted a video that shows the potting-up procedure when I made my seed-starting planters slightly differently… but the video is still relevant: