CROP UPDATE: Spring tasks target perennial fruit/vegetable crops

Posted: Mar. 27, 2013 2:13 pm Updated: Apr. 26, 2013 4:15 pm

Mother Nature just doesn't seem to want to let go of winter this year. I keep hearing everyone say how they're getting discouraged with the March snows, and that each snow adds some moisture to the soil profile. But I'd rather have had the snow in January, and if I had the choice, I'd take the moisture in July.

When we do get spring temperatures, we'll all be wanting to get as much done as possible. And there are always tasks that wait.

Research has shown that the opportune time to remove straw from strawberries is when soil temperatures under the straw are 42-44 degrees. Research has shown that temperature to be ideal. Once the strawberry foliage begins to turn yellow (from the straw preventing sunlight from reaching the growing leaves), yields have been compromised. Likewise, if removed too early, the risk of early growth and blossoms damaged by frost is escalated. Use a soil thermometer to determine temperatures under straw, and time removal accordingly. Placing the straw in the row middles helps reduce weeds and can provide a clean environment for pickers, but keep enough straw in the row to keep the berries off the soil (which can reduce botrytis).

Dead asparagus fern growth can be mowed any time conditions allow. By keeping the fern growth until spring (rather than mow in the fall) two things are accomplished. First, the ferns help to keep the soil cool by shading the sun's rays. This can help to delay the emergence of new spears. Early spear growth is more susceptible to early frost events. Secondly, those ferns help trap snow for possible extra moisture. If you've not soil tested your asparagus patch, it might be worth the effort. I had not soil tested our patch for 15 years (the age of the patch) until last year and found surprisingly low phosphorus levels. And we had been applying moderate levels of nutrients annually.

For 2012 plantings of asparagus or other perennial fruit/vegetable crops (bramble, rhubarb, herbs) that would normally be harvested this year, consider growing conditions last year. If no supplemental water was used throughout last year, you may want to evaluate whether you should harvest this year or not.

Development of root systems for these perennial crops is essential for their long life. It's doubtful if much progress was made in developing these structures, so perhaps for the health and longevity of the planting it might be best to allow another year for development. I know our asparagus we planted last year didn't really grow until the rains of Sept. 1 and after. Before that the ferns were only knee-high. We don't plan on harvesting that planting this year.

Bramble pruning needs to occur now as well. For erect blackberries, remove the dead canes that fruited last year (if not removed last fall). They will be gray in color. For the remaining canes, prune the smallest ones out, leaving a cane every 6-8 inches in the hedgerow. Trailing blackberries follow a somewhat similar regime, removing the canes that fruited last year and leaving 6-8 of the larger canes per plant. Winter cold weather can sometimes cause some dieback of trailing canes, but we wouldn't expect that this year as temperatures never got below 5 degrees.

Red raspberries need tipped back to a 4-6 foot length (depending upon if using a trellis or not) unless your plants are "primocane" bearing plants. These berries are simply mowed off at ground level before they begin to leaf out. Harvest of the primocane begins in late summer and continues to frost.