Strawberry Management Tips

July 17, 2023

Strawberries are a challenging crop, with many management practices that contribute significantly to success or lack thereof. When managed well, they are very profitable. Following are some tips what we consider to be important for successful production. We welcome your feedback.

• Early Preparation
  1. Choose a field. Avoid fields that just came out of peppers, eggplants, tomatoes, potatoes, or strawberries.
  2. Take a soil test. And be prepared to apply a dry blend according to the soil test just before laying the plastic.
  3. Consider two cover crops before strawberries. At minimum, a mustard cover crop should be sowed for suppression of nematodes, phytophthora, and other soil-borne diseases. See termination notes below.
• Variety and Type Selection
  1. Choose a variety based on your needs. Do you want early or later production, or both? Also consider your market. Some varieties ship and store well, but don’t have as good flavor, while others have good flavor but don’t ship or store as well.
  2. Galletta is a popular variety for Lancaster County, but sometimes not available. Chandler is also very productive, with good flavor, but more disease susceptible than some.
  3. Choose bare root or plugs.
     • Bare roots are your cheapest option, but need to be planted in spring for best performance. Do NOT plant bare root in summer during the heat, unless you set up misters to irrigate them for the first week.
     • We mostly recommend using plugs, and planting in mid-August, as this gives you the option to put the disease suppressing mustard cover crop just ahead of the crop. A good quality plug hits the ground running, whereas we often see bare root struggle to establish.
  4. For best selection, order your plants early.

• Preparation
  1. Terminate mustard cover crop about 5-6 days after bloom, and at least 2 weeks before planting. Work into the soil.
  2. Spread compost or mushroom mulch if it fits according to your soil test. Strawberries need lots of nitrogen, Flavorfest needing less than Chandler. Also need potassium. We like the earlier release of potassium coming from composts as compared to slow-release potassium sulfate 0-0-50.
  3. Choose between plastic or matted row.
     • Matted row is the older, original option. Strawberries are planted, then mulched with wheat straw. Runners need to be controlled or the rows will become too thick.
     • Plastic is the more-modern and common approach. Plants and fruit typically mature faster because of the additional heat. And runners do not establish more plants in the row as they cannot root because of the plastic.
  4. If using plastic, consider white versus black plastic. Black is generally recommended, however, white can be considered to extend markets as fruit does not mature as fast.
  5. 4’ plastic is usually used just as for standard raised beds. However, you can also consider 3’ plastic laid just like with sweet potatoes. This prevents water sitting on the bed. The challenge may be keeping straw in place during the winter because of the higher bed.
  6. One dripline should be installed for each row of strawberries (two drip tapes for double staggered rows on 1 plastic).
  7. After plastic is laid, keep moisture there. Run a biological stimulator through the drip about 1-2 weeks before planting. We use Rejuvenate, SeaShield, and Santerra.
• Planting
  1. If planting into black plastic, plant on a cool day, wait till evening, or run overhead misters to establish plants. Then water well to get them started.
  2. Add BioCoat Gold through drip, inoculating roots.
  3. A double row of strawberries is common on black plastic, with 12” to 18” spacing in the row for best air flow and disease control. The spacing is based on whether the canopy of your variety tends to be large or small; Camino Real and Galletta are two that can be spaced on the tighter side. The 2 rows should be staggered as illustrated in the diagram.
• Fall Notes
  1. Focus on root development early, as this has a big impact on nutrient uptake and health of the plant. SeaShield helps, as do seaweeds such as SeaStim. Also calcium and boron.
  2. Run drip weekly till plants enter dormancy. Calcium and nitrogen are the nutrients needed in most quantity in the fall to develop a strong crown that can then fill out a lot of berries in the spring. Then potassium in later fall to fill the crowns. Crown filling is very important as this is your energy reserve next spring.
  3. Epsom salts improve calcium uptake – consider adding weekly or bi-weekly. 10 pounds per acre should be dripped at week 2 as a rooting stimulant.
  4. Strawberries have been known to respond well to applications of SeaShield. SeaShield promotes immunity to diseases and focuses on fungal stimulation in the soil. Strawberries prefer a soil dominated by fungi, rather than bacteria.
  5. The buds for next spring are initiated in September. This is a critical time that sets your maximum yield potential. They need a lot of water during this time. Some varieties may benefit from a bloom stimulant such as Accelerate, although most plants produce more blooms than they have energy to fill out. Applications of Accelerate should be based on experience of each farm.
  6. Mid-September is a good time to take a sap test to determine nutrient levels in the plant. Repeat in early October.
  7. Runners should be removed at least twice in the fall. If bare roots are used, some strawberries may also be produced the first summer. Remove them, as they take too much energy away from the plants.
  8. Monitor occasionally for crown plugging / diseases. To check, dig a plant and split the crown with a knife. The inside should be white. If brown, you may have a problem and may want to seek consultant advice. Brown indicates a clogged “filter” that may prevent water and nutrition from being absorbed even though it is being fed.
  9. We like to see very vigorous plants in the fall, that then go almost completely dormant. Calcium and Epsom salts promote a healthier, robust growth, while too much nitrogen promotes more spindly growth. A balance of calcium and nitrogen is needed.
• Cover crops between rows
  1. We recommend getting a cover crop (or mulch of some kind) between the plastic rows if possible, although much more research needs to be done.
  2. We have tried Turf Star, which is slow growing perennial, and liked it in the fall. However, in spring when mowing, some of grass clipping may get unto the fruit and it may be hard to get all the grass because of fruit hanging out over the side of the plastic.
  3. Oats can be sowed in the fall, which should winter-kill. Then straw or ground covers over top of that in spring for a nice bed. Our concern is that the oats might NOT winterkill if straw or row cover is used. This could be winter dependent. So use caution with this unless tested to work for you.
  4. One grower sowed sorghum sudan in late fall which then winter killed. It worked well, and despite the shading, the plants seemed very healthy.
• Winter Notes
  1. After plants are dormant, they should be covered with a heavy row cover, or 4” of wheat straw (they’re called strawberries for a reason, right?), to protect them from sudden temperature fluctuations, preventing frost heaving which can break the roots and expose crowns to frost damage during the winter.
  2. Winter damage can reduce yield and increase disease by a substantial amount.
  3. We have noticed healthier crowns with less damage once calcium and silica levels are elevated. Zinc, copper, potassium, and high brix content also play a major role in winter hardiness.
  4. Dormancy is usually November or early December, depending on weather.
• Spring Notes
  1. The straw or covers should be removed in March or when the soil temperature reaches 40⁰ at a four inch depth. This prevents the plants from coming out of dormancy too fast and producing strawberries that may then just freeze anyway.
  2. After plants are growing, they need freeze protection. Row covers are fine for colder nights, until temperature reach 34-35⁰, then misting is recommended to keep the plants from frost damage. Mist till after 8:00 to 9:00 am.
  3. Adequate soil moisture is needed during bloom, for calcium movement, which promotes a better quality berry. Also consider calcium foliar every 24-48 hours in this stage.
  4. Monitor for tarnished plant bug and thrips, which cause fruit damage in the bloom.
  5. Ensure the plastic is not choking the newly developing crowns!!!

• Harvesting
  1. Low tunnels help prevent anthracnose, gray mold, & diseases that thrive in wet weather.
  2. Irrigate once or twice per week right after picking. This promotes better flavor than when irrigated just before picking. Watering needs vary depending on soil types.
  3. Potassium is extremely important for a quality berry and filling fruit to a large size.
  4. If root rots or crown plugging occurs, consider frequent foliar applications to help save the planting.
• Renovating Plasticulture Berries after Harvest

If you wish to keep the same plants for two years in a row, they need to be renovated for best production. With proper renovation, yields are usually higher in year two, but the berries may still be smaller. If disease pressure is too heavy, we do not recommend keeping the stand.

Guidelines for renovating:

1. Mow or weed-eat the tops, leaving several inches of growth.
2. Remove any leftover runners.
3. Thin to 3-5 crowns per hole.
4. In summer, drip 20 pounds 16-0-0 twice (20 pounds Urea twice if not organic).
5. Replant missing holes by mid-August.
6. In August, apply 20 pounds 7-7-7 with 5 lb. epsom salt, followed by 10 pounds ProCal (20% calcium) with 10 pounds epsom salt in drip a week or two later.
7. Take sap test and treat accordingly.