March is a busy month in the zone 7 garden as cool-weather flowers and crops go in the ground and prep begins in earnest for the April onslaught of warm weather. Warm weather lawns need fertilizer after the first mowing, either in the form of compost or a balanced lawn fertilizer. And it’s about the last moment when you can safely plant new trees or shrubs before hot weather makes their chances dicey.
When the soil dries out enough (and NOT before) work your garden beds deeply.
Plant transplants of broccoli, collards, kale, cabbage and strawberries this month as soon as you can get into the garden. These crops can grow in cool soil. Plant lettuces, too, but be ready with some floating row cover for that last hard frost that’s sure to come before spring really sets in.
Test the soil where you want to grow tomatoes, peppers and the like to make sure it is not too acid. Tomatoes love sweet soil, and lime must be added at least a few weeks before setting out plants to give the lime a chance to break down into a usable form. Tomatoes don’t go in until ALL danger of frost is past, about April 15 for Zone 7.
Start seeds indoors for tomatoes, peppers, basil, squash, cucumbers and other warm-season crops that don’t resent transplanting. Use grow lights if you have them, or a sunny, south-facing window sill.
Plant sugar snap or snow peas directly in the garden or containers.
Get potatoes in the garden before the end of the month if you can find the seed. Yukon gold is a good variety for this zone because the tubers mature early before the heat sets in.
If you want to start blueberries, now is a good time to plant them. Make sure to plant more than one variety for proper pollination.
Start seeds of your warm-season favorites – such as zinnia, marigold and cosmos – indoors along with your veggies. In fact, think about planting lots of these cheerful plants to attract pollinators to your vegetable beds. They will also attract other beneficial insects.
Start perennial seeds now, too, such as hollyhocks and Monarda. Go ahead and set out the cooler season flowers like calendulas, phlox and snapdragons that you started last month (or buy transplants at your Home Depot Garden Center.)
Keep deadheading your daffodils and hyacinths as they need it, but leave the foliage until it turns brown. That will let more energy get absorbed from the leaves into the bulbs for next year’s blooms.
Deadhead pansies, too, for a longer bloom. A dose of fish emulsion or other light fertilizer won’t hurt about now, as well.
Trees and shrubs
You can plant container grown trees and shrubs now. Make sure they are in holes twice as large as the container, and planted only as deeply as the soil level in the container. Backfill the hole with native soil, not amendments. The tree will thrive if it gets used to the soil it’s growing in sooner rather than later.
Apples may need to be sprayed with fire-blight preventative this month if that nasty disease is present in your area.
Make sure your equipment is tuned up and sharpened for the coming mowing season. Think about picking up a mulching kit for your mower so you won’t have to rake up or bag the clippings and they can give nitrogen back to your soil.
If you have a fescue lawn, leave it at about three inches so it can compete successfully with weeds by shading them out. Mow once a week, no more than 1/3 the length of the blade.
After the first mowing, fertilize warm season grasses, such as centipede, zoysia, St. Augustine and Bermuda either with a good sprinkling of compost and lime or a balanced fertilizer. Read up on what the particular grass in your yard needs, then follow the instructions on the bag of whatever product you buy. Over fertilizing and over watering will stress your lawn much more than doing nothing.