It is no surprise that sweet, fragrant strawberries are the most widely cultivated small fruit in the United States. In fact, annual consumption of strawberries is more than seven pounds per capita, according to the U.S. Department of Agriculture. At only 25 calories per half cup, this low-calorie fruit is an excellent source of vitamins, minerals, fiber, anthocyanins, flavonoids, and phenolic acids. That’s the good news. The bad news is that the fruits are soft and highly perishable.
Most strawberries consumed in the U.S. are grown commercially in California or Florida and shipped all over the country. To compensate for their fragile nature, the berries are harvested for shipping before they are fully ripe, which impacts the flavor. Once picked, they do not ripen further. Also, most commercially grown strawberries are reported to be heavily sprayed for pests and diseases. Growing your own strawberries allows you to pick them at their peak of flavor and control what chemicals, if any, to use on your plants.
ABOUT STRAWBERRIES
The strawberries we enjoy these days are the result of a cross (Fragaria x ananassa) that occurred in the late 1700s between our wild native Virginia strawberry (Fragaria virginiana) and a variety from South America (Fragaria chiloensis). This happy marriage of the two species ultimately resulted in literally hundreds of new strawberry cultivars that are widely distributed globally. The plants are herbaceous perennials with an anatomy and growth habit that are unique among fruit plants as the accompanying photo indicates:
- Crown – This is essentially a compressed stem that produces leaves, roots, stolons, and flowering fruit stalks.
- Foliage – The leaves are trifoliate, which means they consist of three leaflets. They grow low to the ground and can form a very attractive ground cover over the growing season.
- Roots – Although they grow to about 6 inches deep in the soil, most of a strawberry plant’s roots are contained in the top 3 inches of soil, which makes the plant susceptible to both drought and excess moisture conditions.
- Stolons – Commonly referred to as runners, stolons are unique, specialized stems that grow horizontally from buds at the base of the leaves. They spread out or “run” above ground and produce clones (“daughter” plants) at nodes spaced at intervals along the leafless stems. This is how strawberry plants propagate themselves.
- Flowering Fruit Stalk – This structure, which is called an inflorescence, produces flowers followed by fruits about 30 days later. The terminal (end) flower blooms first and produces the largest berry, which is called the “king” berry. The remaining flowers open sequentially producing berries that are slightly smaller than the king berry.
TYPES OF STRAWBERRIES
Strawberry plants are categorized as either June-bearing (short-day) or day neutral. They may look identical, but they differ in growth habits as well as flowering and fruiting characteristics. The type you choose to grow depends on your anticipated uses for them.
June-bearing (short-day). This is the most popular type of strawberry grown in the U.S. The “short-day” name refers to the conditions under which the plant forms flower buds. The buds are formed in the fall when days are shorter than 14 hours or when temperatures are below 60°F. June-bearing plants produce one large crop of large, juicy berries over a period of several weeks during May or June. The actual dates when the berries are ripe may fluctuate from year to year depending on weather conditions and the cultivar being grown. By planting several cultivars of June-bearing strawberries, it’s possible to extend the season a bit. For example, Camino Real ripens early to mid-season followed by Chandler and then Flavorfest with some overlap between cultivars.
Once June-bearing plants finish fruiting, they spend the rest of the growing season producing lots of runners, which result in new “daughter” plants with their own leaves, flower buds, and fruits.
Advantages of growing June-bearing cultivars:
- They produce one large crop over a short period of time, which is advantageous for processing large batches of berries for jam or preserves or for freezing them.
- They bear the largest fruits of the strawberry types.
- They generate a lot of runners, which produce lots of new plants.
- They produce for about three years on average before they become non-productive.
Disadvantages of growing June-bearing cultivars:
- The blossoms should be pinched off the first season to allow the plants to develop strong root systems and vigorous shoots. This means no fruit the first year but a bigger and better harvest the following years.
- A late frost can damage the blossoms, particularly of the earliest blooming cultivars.
- They produce a large crop of fruit for only a few weeks, but then they are done for the season.
- The beds need to be rejuvenated periodically to keep the plants productive.
Day-neutral. This type of strawberry is not influenced by day length. In other words, day-neutral plants bloom and set fruit throughout the entire growing season, which is good news for strawberry lovers who want a steady supply rather than one large crop in June. The plants do stop producing flowers and berries when summer temperatures are above 86°F, but they start producing again once temperatures cool down. Day-neutral strawberries are smaller than the June-bearing type because the plant must exert a lot of energy to continue producing throughout the growing season. Blossoms should be removed from first year plants through June. As of July, the plants should be allowed to bloom and set fruit for the rest of the growing season. That way, you get a strong, vigorous plant as well as a crop of berries from late summer through fall of the first year. In their second year, day-neutral plants start producing a medium-size crop about the same time as the June-bearing varieties. Then, they produce another small crop around mid-summer and a third crop in late summer through fall. Albion, Tristar, and San Andreas are examples of day-neutral cultivars.
Advantages of growing day-neutral cultivars:
- They produce a good yield the first growing season they are planted despite having blossoms removed in the early part of summer.
- They bear fruit throughout the growing season well into fall.
Disadvantages of growing day-neutral cultivars:
- Although this is not necessarily a disadvantage, the berries are smaller than those of the June-bearing type.
- The plants generally last only one or two years before they need to be replaced. In fact, commercial growers tend to treat day-neutral plants as annuals.
- The plants don’t produce as many runners as the June-bearing type.
Everbearing. There is some confusion between day-neutral strawberries and a type called “everbearing.” The two terms are sometimes used interchangeably because both types produce more than one crop per year. Despite the name, everbearing cultivars produce only two crops of strawberries per year – one good-sized crop in early summer and a smaller one in late summer with a gap between the two. Also, this type doesn’t produce many runners. Everbearing cultivars have been largely replaced by newer day-neutral cultivars that bear fruit all season long, produce more runners, are more productive, and produce better quality fruit. Ozark Beauty and Quinault are examples of the everbearing type.
Alpine. This is a type of day-neutral strawberry that grows all season long, but it is a different species altogether (Fragaria vesca). This European variety looks similar to the tiny wild strawberries that grow here in the U.S. The fruits are very small and cone-shaped with an intense strawberry flavor. They don’t spread by runners like other varieties do, so the plants are easier to manage. Alpine strawberries are not typically grown commercially because the fruit is too small and fragile. However, because of their remarkable flavor, they are worth trying in the home garden. Alexandria is an example of an Alpine variety.
CULTURAL REQUIREMENTS FOR GROWING STRAWBERRIES
Strawberry plants are compact in size and take up very little space in the garden. They are ideal for homeowners with limited garden space to grow. The plants can be grown in a pot on a sunny patio, a window box, a hanging basket, a barrel, a strawberry pot, or in a pyramid shaped planter, which can be designed to fit the available space.
Whether you plan to grow strawberries in a traditional garden bed, a raised bed, or in some type of container, the cultural requirements are fundamentally the same.
- SITE – Strawberries require full sun all day or at least 8 hours. So choose a sunny site that drains well. The site should also be free of low spots that trap frosty air in early spring when the plants are in bloom. A south-facing gentle slope or the top of a hill is ideal.
- SOIL – Strawberries produce best in fertile soil with a pH of 5.9 to 6.5. The soil should be loose, free of clods, and free of weeds. Because good drainage is essential for strawberries, the soil should be amended with compost or other organic matter to improve drainage. Excess moisture at the root zone can promote fungal diseases and deprive the roots of oxygen needed for respiration purposes. For this reason, most sources recommend planting strawberries in raised beds or berms.
- WATER – Because of their shallow root system, strawberries require about 1 to 1-1/2 inches of water per week. This is particularly important for day-neutral strawberry varieties. Provide supplemental water, preferably through drip irrigation, as needed to dampen the soil to a depth of 6 to 8 inches. Proper moisture levels are particularly important at several critical times during the life of a strawberry plant: (1) when newly installed plants are getting established, (2) when berries are sizing up before and during harvest, and (3) in late summer through fall when the buds for next year’s fruits are forming.
- NUTRIENTS – When starting a new strawberry bed, have the soil tested several months in advance and amend it based on test results. In the absence of a soil test, about two or three weeks before planting strawberry plants in a new bed, broadcast four pounds of balanced (10-10-10) fertilizer per 100 linear feet of row.
- MULCH – A 2- to 4-inch layer of organic mulch, such as straw (from whence this berry gets its name) placed around the plants will help control weeds, conserve moisture, and prevent ripening fruit from touching the soil.
ESTABLISHING A STRAWBERRY BED
The Virginia Cooperative Extension advises planting virus-free strawberry plugs in late fall or dormant crowns in early spring about three to four weeks before the average date of the last frost, which is generally April 15 to 25 in USDA zone 7a. If you can inspect plants before you buy them, look for specimens with a crown diameter of at least 1/2” or more. Plants of that size will establish faster and produce runners sooner than plants with a smaller crown diameter.
Before planting the plugs or crowns in the prepared bed, make sure they are well hydrated and not dried out. A soaking in water for about 1/2 hour before planting may be beneficial.
Space plants at least a foot or more apart in rows that are about 2 to 3 feet apart. Position each plant in the planting hole so that the base of the crown is at soil level and the roots are just covered with soil. The idea is to avoid planting the crowns too shallowly or too deeply. Before covering the roots with soil, spread them out, backfill with soil, and then firm the soil over the roots to prevent air pockets.
HARVESTING STRAWBERRIES
Strawberries are normally ready for harvest about 30 days after bloom. Once a strawberry turns completely red with no white showing, the color signals that the sugar content is at its highest and the flavor is at its peak. Resist the temptation to pick a berry that still has a white spot at the tip. Once picked, the berry will not continue to ripen and will not be as flavorful as a fully ripe specimen.
To avoid bruising the fruits as you harvest them, don’t grasp and tug them from their stems. Instead, either pinch or snip them from the stem. Leave the green caps attached as well as a bit of the stem. This helps prolong the life of the berry. Harvest all ripe berries, even the spoiled or damaged ones. Any ripe ones left on the vines are an invitation for insect infestations and fungal diseases.
Because strawberries are fragile and easily bruised, don’t pile them too deeply in containers. Refrigerate the berries unwashed until you are ready to use them. Then, gently rinse and pat them dry just before using.
SEASONAL CARE OF THE STRAWBERRY BED
To keep a strawberry bed healthy and productive throughout the growing season, monitor it for moisture and nutrient requirements, look for signs of insect or pest damage, and keep it weeded and otherwise well maintained. A general maintenance schedule is provided below. Adjust the schedule as needed to accommodate weather and growing conditions.
MARCH:
- Early spring is normally the ideal time to establish a new strawberry bed once the soil is dry enough to be worked. However, if the weather is colder or wetter than normal, wait until a little later in spring when conditions are more conducive.
- For established strawberry beds, leave mulch in place to protect the plants from a dip in night-time temperatures.
APRIL:
- Remove the straw mulch from established strawberry beds when the plants resume growing. Move the mulch aside where it will help block weeds and keep the berries clean from rain splash up and mud. In the event of a late frost, spread the mulch back over the plants to protect them from freezing.
- Check older June-bearing plants for new roots that have formed higher on the crown of the plant and are exposed above ground. Mound some soil over the exposed roots to help support the base of the plant and provide good contact between the roots and the soil.
- Start controlling weeds as soon as they appear in spring and continue to monitor throughout the entire growing season. With the onset of warmer weather, weeds become an issue in the strawberry bed because they compete with strawberry plants’ shallow roots for moisture and nutrients. They may also harbor pests and diseases.
- As plants start to bloom in April or May, top dress the bed with compost, well-rotted manure, or an organic fertilizer.
MAY:
- Check that there’s enough mulch around the plants to keep the ripening berries off the soil.
- To protect ripening fruit from birds or other wildlife, such as deer, rabbits, mice and voles, drape plastic bird netting over the rows and secure around the edges to prevent access to the berries.
JUNE:
- Harvest ripe strawberries early in the day after they have dried off from dew.
- Inspect the strawberry bed daily for any signs of insect damage or disease.
- Remove any spoiled or rotting fruits.
JULY:
- Inspect strawberry plants for any unhealthy (diseased) crowns and remove them.
- To keep plants neatly contained within rows, position runners so that they can root within the row. Let them continue growing until the row is about two feet wide.
AUGUST:
- Monitor moisture and provide supplemental water as necessary. Lack of water now affects the yield of next year’s berry crop.
SEPTEMBER:
- Continue monitoring moisture levels and provide supplemental water if the weather is dry.
- Keep monitoring and removing weeds as they appear.
OCTOBER:
- For a fall planting of strawberries, October is ideal while temperatures are still warm. The plants will have plenty of time to develop good strong roots before doing dormant in winter.
- If you plan to plant strawberries next spring instead, this is a good time to prepare the planting site so that the soil will be loosened and free of rocks and weeds.
NOVEMBER/DECEMBER:
- Give the entire bed a final weeding to help reduce weeding requirements for next spring.
- After strawberry plants go dormant, which is generally late November or December, apply a 2- to 4-inch layer of straw over the bed. This will help protect the plants from cold weather, fluctuating temperatures, and soil heaving.
TROUBLESHOOTING
PESTS – Strawberry plants may be bothered by aphids, mites, Japanese beetles, thrips, slugs, and snails. To minimize damage, practice good garden sanitation by removing weeds, grass, and plant debris. Organic solutions include handpicking pests such as beetles, slugs and snails or directing a strong spray of water to dislodge aphids, mites and other smaller pests. Use floating row covers to protect plants from Japanese beetles. Avoid planting strawberries near onions or garlic, which might attract thrips. For extensive information on common pests and diseases of strawberry plants with lots of good photos, visit the plantvillage.psu.edu/topics/strawberry website.
DISEASES – Fungal diseases such as Verticillium wilt can also be an issue. Many problems can be avoided or greatly reduced by buying certified disease-free plants from a reputable nursery. Also, good air flow and elevation above grade in raised beds help reduce fungal diseases. Avoid siting a new bed for strawberries where you’ve grown black raspberries or members of the nightshade family (tomatoes, potatoes, peppers and eggplant) that experienced problems with Verticillium wilt in the past. Place straw around plants to keep ripening berries from touching the soil. Keep the plants picked of all ripe and rotting fruit and remove any foliage that appears diseased. As plants begin to decline, which usually occurs after about three years, replace them with new plants. For more information on common fungal diseases of strawberries and recommended treatments, see Clemson Cooperative Extension publication on Growing Strawberries HGIC-1405.
REJUVENATING A STRAWBERRY BED
Well-tended June-bearing strawberry plants produce lots of runners, which can grow into a thick mat of roots and foliage. As the bed becomes crowded, the plants produce smaller berries that can be difficult to find under the heavy foliage. To solve the problem, rejuvenate the bed about every three years. This should be done soon after the harvest is finished so that the plants have time to develop new leaves and set flower buds for next year’s crop.
To rejuvenate a June-bearing strawberry bed, start by removing any mulch and weeds from the bed. Clip or mow the tops of the plants to within 1” to 1-1/2” of the crown. Rake up and remove all clipped foliage. If you plan to keep the plants in rows, use a hoe, spade, or hand trowel to narrow the rows to about 12” wide. Thin the plants within the rows to one every 6” to 8” apart in all directions, removing the oldest (mother) plants but keeping the healthiest and most vigorous of the runner (daughter) plants. Fertilize the plants with a quickly soluble nitrogen fertilizer such as ammonium nitrate at 0.25 to 0.50 pound or apply 1 to 2 pounds of a balanced 10-10-10 fertilizer per 100 feet of row and water in well. This will promote robust new top growth and new runners. As runner plants emerge, reposition them as necessary so that they stay within the rows. Keep the bed weeded and give the plants at least 1 inch of water per week during dry spells. Renew the mulch with the onset of freezing weather.
SUMMARY
The merits of growing your own strawberries can’t be overstated. Because the plants are so small relative to other fruits, even the homeowner with no available gardening space can grow strawberries in a container. If you’re not sure what type of strawberry to grow, experiment. Grow several cultivars that produce fruit early, mid, and late season. The time and effort put into getting strawberries off to the best possible start will reap sweet rewards. Good siting, good disease-resistant cultivar choices, proper plant density, and good maintenance are all key to keeping a strawberry bed healthy, productive, and enjoyable for years to come.
Cover photo of strawberries in basket: By Pat Scrap from Pixabay
SOURCES
“Homegrown Berries,” A Timber Press Growing Guide (Timber Press, 2014)
“The Strawberry Growing Master Manual,” strawberryplants.org website
Growing Strawberries, Clemson Cooperative Extension Publication HGIC 1405
Growing Strawberries, Pennsylvania State Extension Article
Growing Strawberries in the Home Garden, Rutgers Cooperative Extension Fact Sheet FS097.
Renovating Strawberries in the Home Garden, The University of Tennessee Agricultural Extension Service Publication SP284-B.
Small Fruit in the Home Garden, Virginia Cooperative Extension Publication 426-840.
Strawberry, Plantvillage, https://plantvillage.psu.edu/topics/strawberry/infos
