How to Grow Late Season Strawberries
Traditionally in the Northeast, many farmers and gardeners have fresh strawberries ready in May or June, but after about a month, the season ends and blueberries or raspberries take their place in farmers’ markets and kitchens. With the help of the right plants and a little extra work, though, you could have fresh strawberries for shortcakes in October.
Plants are often classified as being short or long day flowering, meaning that some plants make flowers as the sun sets earlier, perhaps to prepare for winter, while others flower as nights get shorter in the spring, when there is plenty of time for their fruits and seeds to mature.
It turns out that spring strawberries actually form their blossoms the fall before they open, so during short days in the fall, they prepare for the fruit that will ripen the next spring. After those berries have turned red and been picked, however, the june-bearing plants just stop flowering. Strawberry fans reluctantly buy berries from California or Florida.
Fortunately, another type of plant can save the day: day neutral strawberries. Day neutral plants flower regardless of how long the days are, so they continue making blossoms all fall. A number of varieties are available from nurseries, including Albion, which is known for its unbeatable flavor, and Seascape, which has a very long season. Here are some tips for growing day neutrals at your farm or garden.
- Order the plants early in the spring or plant the fall before you’d like to pick them. Whether you order bare root plants or plugs, they will need time to grow healthy leaves and root systems in order to support the fruit. Therefore, the sooner you plant, the sooner you can harvest. At the same time, you can’t plant if the ground is frozen or if hard frosts are expected. Nurseries usually allow you to select the date you want the plants to arrive, so choose a time when you’ll be able to plant safely.
- Take good care of the young plants. If you aren’t able to transplant them when they arrive, make sure that they are wet, but not in standing water, and keep them in a refrigerator. Planting at the correct depth is extremely important; the main stem of the plant, called the crown, should be partially above the ground, and the roots should be totally below the soil and not bent. If possible, plant in the late afternoon or on a cloudy day, and be sure to water frequently.
- Cut all runners and cut blossoms for the first few weeks. Your plants have limited resources, especially the sugars they have made from photosynthesis, and for the first few weeks, you want the plant to put all its energy into growing healthy leaves and roots. Strawberries are known for their ability to produce clones of themselves, called runners, which allow them to fill in garden beds. In addition, flowers are likely to open within the first two weeks. It can be very tempting to get some early fruit or additional plants, but think of it this way: the plant’s limited resources are like a pizza, which at the beginning, you want to split between leaves and roots. If you cut additional slices to get extra plants or early fruit, the leaves and root systems get less. After the plants have four or so leaves, however, you can leave the flowers.
- Fertilize generously. Day neutral strawberries love nitrogen, and the impact of nitrogen on fruit size is quite remarkable. When looking at a fertilizer product, three numbers are usually presented on the container separated by hyphens, such as 13–2–13. The first number refers to the percentage of nitrogen in that product by mass. Commercial plantings can require 60 pounds of nitrogen per acre per year, or about 0.2 oz per square yard, but because the berries use nitrogen over the course of the growing season, it’s a good idea to apply some of that every week or every other week. Leaves should be a dark green color; if they look light or even yellow, more nitrogen is probably needed. Too much nitrogen can lead to soft fruit, but in my experience, most people apply too little.
- Keep the fruit clean. If you’re growing on bare soil, the fruit are likely to be quite dirty after rainstorms. Consider growing in black plastic or applying straw or pine needles around the plants. Violent raindrops can also damage the outsides of the berries and leave scars. Some growers will pull horticultural fabric, such as reemay, over the plants before a big storm.
- Watch out for pests. Birds and slugs seem to like strawberries about as much as we do. Slugs can be managed organically by applying a product like Sluggo. Another issue is Spotted Wing Drosophila, a fruit fly that is known for attacking berries before they become overripe. For home gardeners, the best thing to control is to pick your berries often, perhaps every other day, and throw any bad fruit in the trash rather than letting flies get established in them.