Protecting Vegetable Seed Starters from Rodents & Insects

By Louise Placek

Depending on where you live, you will likely have varmint problems. I have come into the greenhouse early in the morning to find the plug trays literally mined for seeds by mice; they go through the trays and pluck them out. What they don’t eat on the spot they gather in their mouths and deposit somewhere else in the greenhouse. I then find my crops of seeds coming up in pots everywhere, even outside in the garden. If it weren’t so frustrating it would be funny. I have to admit, I have gotten a chuckle or two when we find the caches of seeds sprouting in various places.


I have tried many different tactics to keep the mice out of my trays, but the only thing I have found that really works consistently is reemay (row cover). For those who don’t know, reemay is a very light, spun polyester generally used to cover rows of crops to protect them from inclement weather or bugs. I have used it for a variety of things, and it worked very well to keep the mice out. I lay a piece on top of the bench (because they can get up through the mesh on the bench), and set the plug trays on top of this. At night, (which is when they are so busy), I invert a web tray over each of my plug trays and lay another sheet of reemay over the entire bench and tuck it in under the trays.

I know it sounds like I have gone around the bend, but those little dickens had foiled every other attempt I made to keep them out, including traps. A grower friend of mine has gotten so frustrated with the mice that he has been dreaming up a way to actually suspend the plug benches from the ceiling so they can’t climb up the bench supports. It sounded like a good idea to me, but then one day one of my house cats decided he wanted to go live in my greenhouse and that was the end of the mice. Why didn’t I think of that?

Cat in a greenhouse
Adding a cat to your vegetable growing operation is one way to protect against rodents.

Another problem I have experienced with plug trays is cer­tain insects. The ones I have battled the hardest are thrips and leaf miners. They establish themselves early and cause poor growth habit, stunting and mottling. Since we do not use stan­dard greenhouse poisons, it is a challenge to come up with strategies for keeping these pests off my infant plants. The best plan, of course, is to keep the overall “load” of insects down in your houses. This will be discussed in the chapter on disease and pest control. But even with best intentions and vigilance they occasionally get out of hand. Putting up sticky traps all around the plug bench gets a surprising number of the adult forms of these insects. Bacillus thuringiensis and beneficial nematodes will get many of the soil-dwelling larvae. If you are really frustrated, you could spray with a mixture of insecticidal soap and maybe pyrethrum or neem. Just be aware that these can be kind of hard on those tiny seedlings, so I would only recommend this as a last resort. You will have to figure it out as you go.

Source: Made from Scratch