This is the last of three columns devoted to the cultivation of June-bearing strawberries. The first two columns, “Getting started with June-bearing strawberries” and “Recommended varieties of June-bearing strawberries” can be found online by Googling my name and these titles.
We think of strawberries as a perennial crop, at least the June-bearing varieties, but actually the life expectancy for a well-tended strawberry bed is between three and six years. The intensively cultivated plants grow old, lose vigor and must be replaced. To avoid missing an annual harvest (except in the first year), the gardener should anticipate the last harvest year of an old bed (see post-harvest bed renovation, below) and start a new bed in the spring of that year.
As you read the following account of strawberry culture, keep in mind that the most common reason for early bed failure is weeds
The first growing season
You do not want your strawberries to bear fruit during their first growing season. Inspect your new plants three to four times over the flowering period in early June, looking for trusses of flower buds. Pinching these trusses off as you find them will encourage vegetative growth and reduce plant stress during the all-important establishment year.
From July through early September, runners will emerge and take root between the mother plants. Do not mulch the bed at this point, as rooting of the runners is stimulated by bare wet soil. With an eye to maintaining two-foot-wide rows, select the best of the primary runners (those emerging directly from the mother plants) and pin them to the soil with a handful of moist soil so that they will form roots. Secondary and tertiary runners, those that emerge from the primary runners, should be removed.
In early-to-mid-August, should your plants appear stunted or yellowing, apply an organic nitrogen fertilizer at the rate of 1 pound of nitrogen per 1000 square feet of bed. This can be accomplished with a variety of products, including blood meal, soy meal, fish meal and alfalfa meal. All of these are dry materials that can be broadcast directly over the plants followed by sweeping the dust from the leaves to avoid burning. Follow label directs carefully in calculating the correct amount to apply.
By mid-September you should have a two-foot-wide row of dense strawberry foliage. Continue to remove secondary and tertiary runners through the rest of the growing season.
Each winter, mulch should be applied to strawberry beds when the leaves wilt and turn red, typically in late November or early December. You can use clean straw (not hay), sawdust, wood shavings or pine needles. Lay a six-to-ten-inch layer of the mulch over the entire bed.
Remove the mulch in late March to 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. Recent research shows that it is best to remove the mulch on the early end of the season; doing so results in more flowers. But keep mulch handy to recover the plants at night, should a hard frost be in the forecast.
After removing the mulch, you should fertilize very lightly, applying six ounces of organic nitrogen per 1000 square feet of bed. And start your weed control in early spring.
Harvest begins three weeks after the first blooms, typically mid-June through mid-July. Pick fruits when they are fully ripe (strawberries will not ripen after harvest), pick regularly and pick often. Remove any rotten fruit to prevent the spread of disease. Water between harvests to maintain large fruit size.
Post-harvest bed renovation
Every year, at the end of the harvest (mid-July to early August), your strawberry bed must be renovated, an annual bed thinning and renewal process. This is the time to evaluate the bed. Was there a good yield this year? Did the plants grow vigorously without any serious insect or disease problems? If the health of the bed is in decline, make next year its last and plan to start a new bed in the spring.
Renovation begins by pulling all weeds within the row. Then cut off the leaves above the crowns with a mower, weed whacker or shears, removing them from the garden. The leaves can be buried in the compost pile.
Next, apply an organic fertilizer according to soil test recommendations. This is the main fertilizing time for strawberries and a typical application would be two pounds each of nitrogen, phosphorous and potassium per 1000 square feet of bed. Organic sources of phosphorous include rock phosphate and bone meal. Organic sources of potassium are wood ashes and greensand. All fertilizer materials can be broadcast over the bed.
After fertilizing, till or spade the sides of the rows, narrowing each row to 10 inches wide. As you do this, you are also incorporating much of the fertilizer just applied and any cut leaves that were not removed from the garden.
Finish the renovation process by watering thoroughly. For the rest of the summer, weed, weed, weed. In mid-to-late-August, fertilize again at one half the renovation rate. And keep watering; the strawberry plants need one to two inches of water every week for the rest of the growing season.
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