Here’s an update on my recent seed starting activities. Back on 2/3 I started seeds for arugula, lettuce, mizspoona, parsley and kale. The parsley seed went into 3.5″ plastic pots, one for each variety, while everything else went into a 128 cell plug flat. All those seeds have now germinated, and are growing under my fluorescent lights in our basement. It will likely be another couple of weeks before I start planting any of the greens, while the slow growing parsley will need to be transplanted in other quarters once it is a bit bigger. I have thinned to one plant/cell, and as you can see in the below photo, the seedlings are off to a pretty good start after 14 days.
I’ve been using plug flats for several years now. I started using them when I was volunteering with our local Master Gardener group, and we were growing a 1/3 acre vegetable garden and donating all the produce to the local food bank. We grew all of our own transplants ourselves, and I was one of about three MG’s who grew the thousands of seedlings every year for the garden. It was a lot of work, but I also got a lot of experience in starting veggies from seed, as well as growing them on to harvest! The plug flats helped me maximize space so I could grow all those extra plants in addition to the ones I needed for our own garden.
Plug flats come with different cell sizes but generally fit in a standard 1020 nursery tray. I use either the 128 cell or 72 cell tray for salad greens, herbs, and brassicas. The 72 cell tray gives the plants a bit more room for the roots, and I used it last fall for my cabbage, broccoli and kale seedlings. I tend to let them get bigger before planting, which seems to help keep them from the bird attacks. In the below photo, clockwise from upper left, you can see the 128, 72 and 50 cell plug flats side by side for comparison (with a U.S. quarter).
One of my readers recently asked about the plug flats and how I was using them. I don’t have any hard and fast rules as to which size I use. A lot depends on how many seeds I am starting, how much room I have under the lights at the time, and if I plan on transplanting the seedlings into other containers before planting. For instance, I would probably use the 50 cell flats for tomatoes and peppers if I wanted to avoid having to transplant. But since I grow a lot of tomato and pepper plants, that would mean I would need six or more plug flats to accommodate all the plants, which takes up a lot of space under the lights. Instead, I usually start them in two 200 cell plug flats. That lets me seed 400 in two flats. After about three weeks, I transplant into bigger containers, which also lets me set the plants a bit deeper. I also cull any of the weaker plants at that time.
Since I started parsley seeds in 3.5 inch pots, I will prick them out and pot them up into individual containers once they start showing their true leaves. Rodale’s Illustrated Encyclopedia of Herbs says that all the umbelliferous herbs “resent transplanting,” but I’ve found that I can pot up the parsley while still small and it does just fine. In The New Seed-Starters Handbook by Nancy Bubel the author mentions that she often starts parsley in her greenhouse before setting outside, so the admonitions about transplanting aren’t universal. I think the trick is to disturb the roots as little as possible, and then get them planted in the ground before the plants get too big and root bound.
Next up in my seed starting activities will be the spring planted brassicas, followed by the peppers, tomatoes and eggplant. I also need to get some Wave petunias going soon, since they take a fairly long time from seeding to planting out. You can find my general timeline in my Seed Starting and Planting Schedule. I hope you have enjoyed this update, and I’ll be back soon with more happenings!