Weymouth, Mass. — Two berry crops - strawberries and raspberries - rewarded us beyond all our expectations this past season. I recalled this with gratitude the other day as I repaired a broken stake at one end of a raspberry row.
Inevitably, I wondered if next year would be as good. Then in the same instant I realized there was much that could be done this fall to help ensure a good harvest next summer.
Topping the list in this get-ready-for-winter program is mulching. Spreading a layer of organic matter around over-wintering plants does much the same thing for them as a cozy comforter does for us when we go to bed on a cold night.
Mulching does several things for plants. It reduces the depth to which soil freezes so that frequently deeper roots can draw up the minuscule amounts of moisture that even dormant plants need in winter. More important, it prevents the rapid freeze-thaw cycles which periodically take place in winter which can heave plants and snap tender roots.
Soil that has been sheltered by mulch during the winter has much better texture to it in the spring. I find the mulch filled with earthworms just as soon as the frost leaves the ground and they do much to improve the physical structure of the soil. Finally, all during the growing season the mulch slowly decays to feed the plants. At this writing, little remains of the thick mulch I applied to the berries last fall.
Strawberries like nothing better than a mulch of old horse manure. Lacking that, straw makes as excellent winter cover. So do shredded leaves or a mixture of all three. I packed an inch of shredded leaves on top of a light application of shredded newspaper (black-ink pages only) around the strawberries last fall. Then I added a further sprinkling of shredded leaves until virtually all the leaves were covered. This packed down to perhaps a 2-inch-thick mulch under the winter snows.
Come spring, conventional wisdom suggests that much of this mulch should be removed. However, I elected to leave it all in place last spring and watch what happened. The new growth appeared to have no difficulty pushing its way through the mulch and pretty soon the whole bed was a mass of bright green leaves.
An abundant berry crop, considering the small size of the bed, followed in June.
Whether the mulch delayed the bed from warming up by much, I do not know. Perhaps the fact that the bed is raised compensated for this. At most, the harvest could not have been delayed by more than a few days.
With raspberries, mulching is just the first of several steps needed to prepare them for winter. I throw between 4 and 6 inches of shredded leaves around the base of the canes and a similar thickness goes down the paths between the berry rows. Often I use whole leaves on the paths, simply because I do not have time to shred all the leaves I need.
The problem with using whole leaves is that they can mat together to form a tight layer that is impervious to both water and air. So in the spring I walk down the rows, fluffing up the leaves with a garden fork. One such operation has always proved adequate in my experience.
In the coldest regions of the US, raspberry canes frequently are bent over and pinned to the ground, then covered with straw or other appropriate protective materials. Thereafter, falling snow provides additional protection. This is done to prevent winter-killing the canes that bear next season's fruit.
Here in coastal New England, such drastic steps are unnecessary. But any protection from cold, drying winds that you can provide will be helpful.
First, trim back the canes to between 4 and 5 feet tall. This makes for a sturdier cane that will not blow around in the wind quite as much. Next, gather the canes in clumps and tie them together with strips of old sheeting or old nylons. This prevents wind damage (the canes won't batter against one another in a gale). And, like cattle clustering together for shelter, the canes afford mutual protection when drying winds blow.
You might also tie down the branch of an evergreen on the windward side of each clump of canes for still further protection. In the spring throw the evergreens on the paths for additional moisture-conserving mulch. Another, but more expensive option, is to encircle your raspberry patch with a screen of burlap.
In the spring, a light application of nitrogen-rich fertilizer will get your canes off and running.
All this takes a little time and effort. But, oh, how delectable are the rewards!