by Gary Mount
Terhune Orchards’ strawberry harvest season is just around the corner. Strawberries are one our first crops each year and also one of our best. Red, juicy, sweet, great refreshing taste – all those adjectives apply to strawberries. But when the days warm and the strawberry plants start to wake up and grow, much of the work in strawberries is already complete. Strawberry production starts in June of the previous year. We pick a field fairly close to the farmstore so that the berries can be harvested pick-your-own without too long of a walk. But the field also should not have had strawberries planted for a few years. Planting the same crop in the same place year after year allows diseases and insects to build in the soil. It also depletes the specific nutrients needed for that crop to grow and produce a good tasting fruit.
Next we plow the site and make raised beds in the soil with a trickle irrigation tube buried in the bed and a cover of black plastic over each bed. The raised bed protects the plant roots from being flooded when we get downpours during the growing season. The raised bed and the black plastic cover also help the soil warm quickly in the spring – promoting good plant growth. The black plastic keeps weeds from growing and keeps the berries off the soil, which is a source of disease. The trickle irrigation tube provides water and nutrients during the growing season (more about nutrients later). As little as one week of severe dryness can stunt the plant and the crop. Even if followed by adequate watering, the strawberries will never get to where they should be.
Finally we are ready to plant, which we do in two ways. In early July we plant bare root plants. These plants are purchased from a nursery, which dug them in the fall and kept them in cold storage – about 33 degrees – until it was time to ship them to us in July. We also plant some strawberries at the end of August. These are actively growing plants that were started at the nursery in June and shipped to us in flats much like the flats of pansies that might be seen at a garden center.
We take care of the plants all summer and fall – taking care of weeds, insects, disease, watering, excluding the geese (the geese must think strawberry plants are some sort of candy), watching out for rabbits and deer. In late October, we cover the field with a white sheet material called floating row cover, which protects the plants from severe winter temperatures.
In the spring we watch for the first strawberry flowers to appear under the cover.At that time the covers must come off so bees that we bring into the field can pollinate the flowers. But – and this is a very big but – the strawberries are at their most vulnerable stage of growth during this period. Strawberries bloom early, during a time when spring frosts are prevalent. Freezing temperatures will kill the flowers, causing them to turn black and drop off. In the strawberry business, dead flowers mean no strawberries. So when we take off the covers, we install, on the same day, an overhead irrigation system for the field. If freezing temperatures occur, the irrigation is turned on. As the water freezes on the plants and flowers, it liberates heat. As long as water is continuously applied and it doesn’t get too, too cold, the plant temperature will not go below 32 degrees F and the flowers will live. This might be hard to understand unless you think of what happens when ice is put in a glass of water. As the ice melts, it makes the water colder. Out in the field, it is just the opposite. As the water freezes and makes ice, it makes the plant warmer. Simple, right? Trust me, it works.
After about 4-5 weeks the strawberries will be ready to pick. During this period, it is very important that nutrients are available in the soil for the plant to use while the berries are growing. Berry size, color, taste, firmness and sweetness are all affected. I attended a lecture this winter given by Steve Bogash, a Penn State ag extension agent. One of his specialties is strawberry production. He advises his growers to have strawberry plant tissue analysis done every week in the spring. This way the grower can know what the plant is actually getting from the soil and what is lacking. Nutrients, similar to the miracle-gro used on houseplants, can be mixed with the irrigation water fed through the tubes going down each raised bed. The plants get the nutrients immediately – it shows in the next week’s analysis! I think I will be doing some tissue analysis this spring.
So all this to grow a strawberry. It is complicated, painstaking and expensive. But, if we do it right and the weather cooperates, what a reward. Come on out and pick some strawberries this year. They should be ready about mid May.