By Susanne von Rosenberg, UC Master Gardener of Napa County
January is a great time of year to plant strawberries in Napa Valley, regardless of online recommendations to plant them in the spring, late summer or early fall.
Strawberries come in three types: June bearing, day neutral and everbearing. June-bearing strawberries set one heavy crop in late spring, typically starting in mid-May in our area for the early varieties. They produce most of their berries in a window of 10 to 14 days, and they tolerate hot temperatures. June-bearing strawberries come in early-, mid-, and late-season varieties. The late-season varieties start fruiting about two weeks after the early varieties.
Day-neutral varieties will fruit as long as the day length is 12 hours or more and temperatures remain between 40°F and 90°F. Despite their name, everbearing strawberries will produce a fairly heavy crop in late spring and again in early fall. They may produce a third crop in mid-summer in mild summer areas.
Sources disagree about which type of strawberry plants produce the biggest berries. But unless you want large berries for decorative reasons, don't let size affect your choice as it has no correlation to flavor.
Many strawberry varieties do well in our area. In 2012, the Master Gardeners did a field trial of three varieties, and Albion (a day-neutral variety) performed best. Sequoia (an everbearing variety that can produce all season in mild climates) also did fairly well, but Quinault, a popular everbearing variety, performed poorly.
Other good day-neutral varieties include Seascape and Selva. The latter is notable for its large berries. Good June-bearing varieties include Chandler, Jewel, Camarosa and Ventana.
Not surprisingly, catalogs tend to describe all the varieties as having great flavor, so just experiment and see which you prefer. One source said Jewel had an “exotic tropical fruit flavor.” Camarosa and Chandler are said to produce large yields.
Everbearing varieties seem to be losing ground to day-neutral varieties. To make matters more confusing, a lot of catalogs and online sources use those terms interchangeably, although they clearly aren't the same.
Look for certified disease-free, bare-root plants from a local nursery. Big-box stores sometimes have six-packs of strawberry plants, but often with no indication of variety. Think twice about buying these as you won't know if they're suited to our climate, or when the plants will bear fruit.
Strawberry plants will produce the year you plant them and will typically have their best crop the following season. After that, production will decline. Expect to replant about every three years. You can grow your own new plants from runners. June-bearing plants will produce the most runners, whereas everbearing and day-neutral varieties put more of their energy into producing fruit.
If you don't want to grow replacement plants, cut off the runners because they take energy from fruit production. It's also best to cut off runners in the first year to help the plants get established. Leaving a few runners to fill bare spots is okay.
Strawberry plants need at least eight hours of sunlight a day. Don't plant them where you recently grew members of the Solanaceae family, such as tomatoes, eggplants, peppers and potatoes. All these plants are susceptible to verticillium wilt, a fungal disease. By rotating where you plant Solanaceae, you can keep the fungus from getting established in the soil.
Slugs and snails are the primary pests of strawberries. Pick them off by hand, or use an iron phosphate-based bait. These baits are non-toxic to other animals. Strawberries can also suffer from nutrient deficiencies. (I had an issue with lack of boron.) Check online sources if your berries look odd.
Plant your plants so that the crown (center growing point) is just above the soil level. Strawberries need regular water, especially during fruit-bearing season. Use drip irrigation with emitters at least two inches away from the plant to minimize the risk of fungal disease. Keep the soil moist—strawberries are shallow-rooted—but let the top of the plant dry out between waterings to avoid rot. Don't plant strawberries near irrigated lawn or where they might be watered by overhead sprinklers.
Strawberries like well-drained soil. Raised beds with 12 to 18 inches of soil are ideal, or mound up your garden soil to a depth of 6 to 8 inches. If you are growing strawberries in a container, be sure they have 12 inches of soil as well. Those special strawberry planter pots are attractive but often not that effective because they don't hold enough soil. Use them for growing annual herbs instead.
Strawberries do not need a lot of fertilizer. One application of a slow-release or organic fertilizer at planting time is adequate for the first season. Fertilize again in late summer or early fall for the following year.
Workshop: Napa County Master Gardeners will host a workshop on “Pruning and Plant ID” on Saturday, January 29, from 10 a..m. to noon at Las Flores Community Center, 4300 Linda Vista Avenue, Napa. Bring gloves and wear gardening attire for this hands-on workshop. To register: https://ucanr.edu/2022JanLasFloresLearningGardenPruning
Library Talk: Napa County Master Gardeners will give a talk on “Creative Cucurbits: Loofahs and More” on Thursday, February 3, from 7 pm to 8 pm. Save room in the garden for some crazy cucurbits and learn how to prepare them for your own use or as gifts. Register to receive the Zoom link at https://ucanr.edu/2022FebCucurbits.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email.
For more information visit https://napamg.ucanr.edu
By Susanne von Rosenberg, UC Master Gardener of Napa County
One of the joys of summer is being able to harvest fresh, perfectly ripened fruit from your own garden. December and January are the best months to plant bare-root fruit trees and berries so you can enjoy the bounty in summers to come.
Unlike fruit trees, most berries provide a quick return on your efforts. Strawberries bear fruit the same year you plant them, and blackberries and raspberries produce the year after you plant them. Blueberries are more complicated to grow (they need acidic soil to thrive), but also usually start to produce some fruit in the second year.
Berry plants are less expensive than fruit trees, and if you choose the right kinds, you can expand your berry patch over time. The main drawback to berries is that they all have relatively high water needs.
Brambleberry is another name for blackberries and raspberries. Boysenberries, marionberries and ollalieberries are all varieties of blackberries. Blackberries are well suited to our Napa Valley climate. (In fact, boysenberries were developed here.) Raspberries also do well in all but our hottest areas.
While it's easy to get blackberry and raspberry seedlings from friends (many brambleberries produce suckers from their roots), it's best to start with certified disease-free nursery stock. You can always expand your berry patch by planting some of the suckers. Blackberries and black and purple raspberries also tip-root. If the tip of a cane touches moist ground, it will grow roots from that tip.
To produce well, brambleberries should be planted in full sun. In hotter areas, raspberries benefit from some afternoon shade. Care of brambleberries is fairly simple. Fertilize them once a year at the start of the growing season and keep the soil moist, not soggy, throughout the growing season. The berries also need pruning each year.
Blackberries yield fruit on canes that grew the previous year. The canes growing in the current year are called primocanes. Nurseries sell both erect and trailing varieties of blackberries; trailing varieties need a trellis. Erect varieties have sturdier canes, but the canes will still tip over when they get long, so these varieties also benefit from a trellis. Install trellises when plants are small to minimize root damage.
Most blackberry varieties have thorns, but there are thornless types. I used to be suspicious of thornless varieties, assuming that I would have to sacrifice flavor or vigor for convenience. A couple of years ago, I finally tried a thornless variety, Triple Crown. I was happily surprised by the great flavor and vigor, both of which compare favorably with the boysenberries I have been growing for a long time. To extend your harvest, choose blackberry varieties with different ripening periods.
Raspberries come in four colors: red, yellow, purple and black. The cultivation process for yellow and red raspberries is the same. Red raspberry varieties come in two types: summer bearing and fall bearing. Summer-bearing raspberries produce canes that grow one year, then primarily bear fruit the following year. Summer bearers produce some fruit on the tips of the current season's canes, but a larger crop is produced on one-year-old canes.
Fall-bearing raspberries do the opposite: they bear large crops on the top parts of the current season's canes in late summer and fall. If left to overwinter, canes bear a second crop in the spring, on the lower portions of the canes that fruited the previous year.
My new favorite red raspberry variety is Nova. It is vigorous, has great flavor and has consistently been the earliest and latest producer in my raspberry patch.
Black raspberries (you may have heard them called black caps when you were growing up) and purple raspberries grow on arched or trailing canes. Black and purple raspberries only sprout new canes from the crown (the base of existing canes) or through tip-rooting. Fruit grows on laterals coming from the main canes, so they are pruned differently from blackberries and red raspberries.
To keep your berry patch fruitful, prune out the old (non-fruiting) canes and excess canes. Remove fruiting canes of blackberries and summer-bearing raspberries after they are done fruiting. Then tie up the primocanes.
For trailing varieties, cut the new canes to 8 to 10 feet and loop them around the trellis wires. Fall-bearing raspberries can either be cut to the ground after the fall crop, or you can cut off the top portions of the canes that fruited and get a small spring crop on the lower parts of the canes.
Prune black and purple raspberries to a height of 24 to 30 inches after fruiting. In early spring, cut back any laterals that sprouted to 8 to 10 inches. During the dormant season remove all dead, damaged, weak and diseased canes from all brambleberries. Remove all but 4 to 5 of the most vigorous canes from the crowns of black and purple raspberries and 8 to 10 canes for blackberries. Aim for 4 to 5 strong canes per foot for red raspberries. With the right care through the year, your berries should provide a bountiful harvest.
Napa Library Talks: First Thursday of each month. Register to get Zoom link. Thursday, January 7: Bare Root Basics.
Free Rose Pruning and Winter Care Workshop: Saturday, January 9. Register for the Zoom link.
Got Garden Questions? Contact our Help Desk. The team is working remotely so please submit your questions through our diagnosis form, sending any photos to mastergardeners@countyofnapa.org or leave a detailed message at 707- 253-4143. A Master Gardener will get back to you by phone or email. For more information visit http://napamg.ucanr.edu or find us on Facebook or Instagram, UC Master Gardeners of Napa County.
- Posted by: Yvonne Rasmussen
- Author: Jane Callier
There are two types of strawberries: day-neutral varieties, also called ever bearers, and short-day types.
Ever-bearing plants are not affected by day length and have their highest production from spring through fall. Short-day types produce from fall through early spring when days are shorter. In our area, ever bearers are generally considered synonymous with day neutrals.
Your strawberry plants will need at least eight hours of full sun each day to produce well. Strawberries grow best in loamy or sandy soils. Before planting, prepare the soil by incorporating two to three inches of compost or other organic matter to a depth of at least 12 inches. Organic matter improves nutrient availability as well as the soil's structure and water-holding capacity.
Dig in some balanced fertilizer as well. Strawberries may still need to be fed several times during the growing season. Poor vigor or light green leaves tell you that it's time to fertilize. Heavy clay soil hampers strawberry growth and vigor and encourages disease, but you can succeed with clay soil if it is well drained. If possible, plant strawberries in raised beds to improve soil drainage and aeration.
When planting, remove any dead leaves, spread the roots out in the planting hole, and firm the soil around the plant. The crown of the plant — the area between the roots and the leaf stems — should be even with or slightly above ground level. Water the transplants well. Strawberry plants have shallow roots and need to be kept moist during the growing season. Use drip irrigation to keep moisture away from the fruit, minimizing fruit rot. Strawberries don't compete well with weeds, so be a vigilant weeder to extend the life of your beds.
Think about your strawberry bed as a temporary structure. Relocate plants after three to five years to prevent buildup of soil-borne pathogens. Avoid planting them in areas where you have recently grown other members of the Solanaceae family, such as peppers, tomatoes, potatoes, eggplant and okra. They are all subject to the same soil-borne diseases.
Napa County Master Gardeners recently completed a year-long field trial of three markedly different strawberry varieties. We grew two day-neutral varieties, Albion and Quinault, and one short-day variety, Sequoia. Trial participants planted bare-root seedlings in January. Some gardeners planted in containers, which work well because of the plants' small root systems.
Following common practice, we removed runners the first year to strengthen the mother plants. Some gardeners also removed the first flush of blossoms and consequently harvested a meager amount of Sequoia berries, if any. Most of us used straw mulch to retain soil moisture and keep fruit off the ground, away from earwigs, sow bugs, snails and slugs.
Birds pecking at ripe fruit were among the most annoying pests; some gardeners used netting to control them.
Fruit production varied. The Sequoia plants produced some huge, sweet berries but finished production before hot weather began, leaving us with the impression that its growing season was too short.
The Quinault plants yielded smaller, very soft fruit that needed to be eaten almost immediately. A few growers complained about having to throw away so many Quinault berries because they were too soft.
Albion berries were by far the best producers, yielding large, sweet, conical fruit on upright stems. Currently, the Albion is one of the most popular strawberry varieties in California. It was developed at the UC Davis and introduced only a few years ago. Photo of some of our harvest of Albion strawberries grown at our demonstration garden.
Our group kept yield records through Oct. 31. However, several gardeners, as well as their children and grandchildren, succumbed to temptation and ate some of the juicy crop before it had a chance to be weighed.
Consequently, our results are not rigorously scientific.
Roughly speaking, Albion berries accounted for 67 percent of the total yield, Quinault berries 25 percent and Sequoia berries 8 percent. Most of the participants intend to keep their plants going for another year.
For more information on growing strawberries and strawberry pest information see the UC integrated Pest Management website http://www.ipm.ucdavis.edu/PMG/GARDEN/FRUIT/strawberries.html
Napa County Master Gardeners ( http://cenapa.ucdavis.edu) are available to answer gardening questions Monday, Wednesday and Friday, 9 a.m. to noon, at the UC Cooperative Extension office, 1710 Soscol Ave., Suite 4, Napa, 253-4221.
