Framed by uncertainties of weather, here are a few garden tips for April. They were gleaned from my upcoming book, “The New England Gardener’s Year, a Month-by-Month Guide for Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, and Upstate New York,” to be published later this year by Cadent Publishing.
Build a raised bed (or two)
I am in the process of building two 4-by-8-foot raised beds for our garden. To keep the cost down, I purchased rough-cut 2-by-10-inch spruce lumber and plan on lining the inside of each board with plastic to slow down the rotting process.
The beds, filled with screened loam amended with composted manure, will be used to grow rhubarb and asparagus in a full-sun area of the yard, a site with thin, poor soil.
Heel-in early arrivals
The rhubarb crowns arrived last week, before their bed was ready, and the asparagus crowns could arrive any day. Early arrivals, if kept in the shipping box, will lose water and their buds may die. To temporarily store them, I used a technique called “heeling in.” After digging a shallow trench in one of the garden beds and propping the crowns, buds up, against the side of the trench, I covered them with soil so the buds were just below the soil surface. They will keep just fine for a week or two while I finish those beds.
Sow seeds of early-spring crops
You can sow seeds of Swiss chard, beets, green onions, kale, kohlrabi, peas, radishes, spinach and turnips in April, but only when the soil is workable. To check the condition of your soil, pick up a handful from one of the garden’s beds and squeeze it in your hand. If it remains in a tight clump after you release your hand, or if you can actually squeeze water out of the soil, it is still too wet to work. If it falls apart with just a little gentle prodding, grab a spade or fork and get to work, but keep your feet in the walkways. Walking on soil in which plants will be growing is never a good idea as even dry soils are compacted by foot traffic.
Your chances of getting seed sown in April will be enhanced if you are gardening in raised beds. Raised beds warm earlier and drain faster than the surrounding soil.
Small seeds, such as those of carrots and lettuce, are often difficult to sow thinly and the end result is crowded seedlings that need early thinning. For better seed spacing, try mixing some sand with tiny seeds. Or, mix the fine seeds in very soft gelatin, then put the mixture in a squeeze bottle (an old mustard bottle, for example) and squeeze out the mixture into the prepared furrow.
Try growing vegetables in containers
While waiting for the soil to dry out and warm up, try planting cold-hardy crops, such as carrots, beets, lettuce, spinach and green onions, in containers. Use a soilless potting mix such as ProMix or one of the Fafard mixes, adding composted cow manure, worm castings or compost as a nutrient source at one part compost or castings for every four parts soilless mix. Be sure to wet the mixture thoroughly before sowing seeds.
Plant some early potatoes
I usually wait until the first of May to plant my seed potatoes, but last weekend, at Ellsworth Feed and Seed, owner Harvard Jordan told me that he always plants Red Pontiac potatoes in the first week of April and enjoys new potatoes for supper in June. He plants these early seed potatoes shallow, in warmer soil.
Uncover and fertilize strawberries
Remove the winter mulch from strawberry plants in early April, tucking it under and around the plants and moving the excess into the walkways, keeping it handy for protecting plants from a late frost. Strawberry buds and flowers will be killed by a hard frost if left exposed, yet research shows that it is best to remove the mulch on the early end of the season; doing so results in more flowers.
After removing the mulch, fertilize the plants lightly, applying six ounces of organic nitrogen per 1,000 square feet of bed. This can be accomplished with a variety of organic products, including blood meal, soy meal, fish meal and alfalfa meal. All of these are dry materials that can be cast directly over the soil between the plants, followed by washing the dust from the leaves to avoid burning. Follow label directions carefully in calculating the correct amount to apply.
Plant cabbage transplants
Cabbage seedlings, either homegrown or purchased from your local garden center, can be transplanted to the garden in April, again only when the soil can be worked. They should first be hardened off by exposing them to outdoor conditions over the course of a week with above-freezing temperatures, leaving them outside an hour or two longer each day.
Set the hardened transplants 18-24 inches apart in soil amended with aged manure or compost. If planting in rows, space rows 2-4 feet apart. Do not apply excessive fertilizer, as high nitrogen levels result in poor head shape and reduced yields. For uninterrupted growth, the planted area should receive one inch of water per week from rain and-or irrigation.
Start weeding — and keep weeding
Some garden weeds, such as quackgrass and chickweed, start growing early in the season and are soon producing seeds if left unchecked. Get them out of the garden as soon as you notice them.
Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to firstname.lastname@example.org. Include name, address and telephone number.