Organic food farming - crop protection using row covers
If you have done any gardening in cooler climates, (or read about it) you have probably heard about row covers as a crop protection device. Row cover is a big thing at New Terra Farm, we buy and use (and re-use, when we can) a LOT of it.
Row cover works great as protection against frost for early crops, and as a physical barrier to many insects. But it only works well if you use it properly. Here's a few things we learned about using row cover at New Terra Farm.
We use row covers on raised beds to protect transplants. Note that for early plantings, that may receive a substantial frost,we build a little wood-and-wire frame (see pictures) to drape the row cover over. This keeps the fabric from direct contact with the plant; this is important because the plant may be frost-burned if it is touching.
We have put transplants of cold-tolerant vegetables (e.g. broccoli, cabbage, onions, lettuces) in the garden as much as 5 weeks before our last frost date, and we have never lost a crop that was protected this way.
We also use row cover as an extra layer of protection for our cold frames. If temperatures threaten to get REALLY cold after we have started the cold frames, we drape row cover over them in the afternoon, and anchor it on all sides.
Row cover can also help germination of direct seeded crops e.g. like carrots, beets, spinach. Plant your seeds, water thoroughly, and cover.
If you are using row cover as an insect barrier, you have to be ready to install it as soon as you put in the plants. We use row cover to protect our brassica's and many of our lettuces and greens. These plants don't need to be pollinated by insects, so we leave the row covers on right up to harvest. This works because we use drip irrigation (installed before the row cover goes on) to water, and lots of mulch to suppress weeds. We get insect-free crops (well, 90% or so) without using chemical pesticides.
We wrap our tomato cages with plastic on the sides, and row cover over the top, to create a min-greenhouse for the plants. This helps to retain heat for the early plantings and speeds ripening. We do the same for peppers.
The key to using row cover right is to make sure it is anchored well. The only way we have found to do this effectively is to bury all the edges in the soil. We have tried to anchor the edges with pins, stakes, rocks, re-bar, etc but nothing stands up to the winds we get except burying all sides with dirt. We use a hand tool called a Ho-Mi digger. It looks like a miniature plowshare on a long handle, and its an efficient tool for this task.
Row cover and frame in the 'shady garden'