CARRY-OVER PROCEDURES

Vegetable Growers News
May - June 2001, Vol. 8, No. 3

Charlie O'Dell Extension Horticulturist, Virginia Tech

Many strawberry growers, especially following a poor cropping season in their particular location, ask about carry-over or renovation practices, what to do, when to do it. This time of year is a good time to review these procedures, in case you are considering carry-over versus re-planting. If you are in the southern piedmont, southeastern and tidewater areas of Virginia, we do not recommend carry-over because of added risk of Anthracnose Crown Rot in these hotter, more humid areas. For upper piedmont, northern, western and southwestern areas, IF fields are disease-free, you may wish to consider it. In these areas, most often your second year crop will out-yield your first crop because of extra branch crown development at these colder areas by the second crop year. One time during a daring fit of wild cantankerousness, we kept over a field for the third year even though the plastic mulch was getting tattered. Due to excellent mild winter and spring that year, the third year crop was our best crop of the three years here in "the North Pole of Va."! From over eleven years of experience with carry-over here where we always carry-over, (we have never not-carried over), we found that berry size will be slightly smaller on years two and three, but are still very acceptable for U-Pick enterprises. Carry-over berry size will not be as competitive for wholesale marketing as those first year primo size berries. However, we would quit growing berries before we ventured into that cut-throat arena!

Anyway, as cooperative berry breeding efforts are able to develop hardy, disease-free varieties for our areas, then we can run with them for 2 and even 3 cropping years for profitable production. Right now, one break-even crop of strawberries followed by double cropping to pumpkins or other fall vegetables, is an expensive way to grow the vegetables, in my way of thinking. We do the pumpkins after the second or third year crop. Thanks for your patience while we are eagerly awaiting a carry-over variety or varieties for our areas north and west of Raleigh, NC! For now, ole cro is playing with that loaded gun, so far so good...

Plasticulture Strawberry Renovation that Works for Charlie O'Dell:

1. By July 1. Broadcast spray 2,4-D Amine, labeled formulation, 1.5 Qts/acre. Note: If plant-killing diseases are present, do NOT carry over planting, desiccate plants, double crop to fall vegetables.

2. By July 14. 2 weeks after spraying 2,4-D, mow off berry plants 2" above crowns.

3. By July 15. Drip irrigate to wet beds well (on our heavier soils here, requires about 7 hours of drip at 12" in-line emitter spacing, beds on 5' centers, to equal 1 acre inch of water to beds). On sandier soils, will require more frequent, shorter cycles. Apply no fertilizers to beds during summer months. Goal: keep plants alive, but not fast growing (controlled moisture stress).

4. Every 3 weeks through end of August, same as #3 above.

5. September 1, take plant tissue analysis and soil test the beds. Typically in this area carry over beds will test high in N, medium to medium low in both P and K.

6. Sept. 15, Drip irrigate to wet beds well and fertigate nutrients as per soil test and plant sufficiency needs, typically here may need 15-20 lbs/A of P and K, less of N, with solubles or liquids as 12-48-8, 9-45-15 followed by 8-15-36. Mixing high K analyses with other grades will cause salting out or heavy fertigator-clogging precipitates, use in sequence.

7. September 20, Spray row middles with Gramoxone, shielded sprayer only, for all vegetation including rooted berry runners filling row middles. If foxtail or other tall grasses have invaded row middles, first use Poast, crop oil plus ammonium sulfate as per Poast label recommendations prior to using Gramoxone. Remove crop shields for Poast spray and raise spray boom to high position to completely spray overtop of grasses in middles.

8. October 1 and 15, Last drip irrigations of the season, wet beds well. Field mice and voles may be moving into beds for over wintering, use vole baits under plastic mulch where it cannot be reached by pets, birds or people, otherwise drip tapes may be cut and destroyed by voles and field mice.

9. October 16, winterize and drain all drip components, filters, lines. Order heavy winter/spring crop covers, don't bet on a "Carolina winter". In colder areas as here, 1.5 to 2.0 oz/sq.yd. covers are recommended.

10. Late December, after carry-over plantings have gone dormant and turned brown (they do not remain green overwinter as in the planting year, but adapt as do hardy, eastern varieties, by going dormant), apply heavy crop cover, weighted every 10' around perimeter with 8" cinder blocks or rock-filled plastic mesh oyster bags.

11. Early to late February depending on severity of the winter season, remove winter crop covers, leave secured on NW windward side for re-use for heavy severe freezes and for re-use for frost control during later spring bloom period.

12. February as weather permits, if you use sprinkler irrigation for frost control, set up and test the system well ahead of expected bloom season.

13. Early February to early March, as weather permits, clean off dead runners and dead leaves from the beds back to the mother plants. Check out mechanical brushes, high vacuum mowers and plastic leaf rakes and leaf blowers to replace/reduce hand labor of this vital chore which also helps rid beds of Botrytis Gray Mold Fruit Rot inoculum. Dead leaves and runners are the primary source of spores for Gray Mold to infect new spring leaves and blooms.

14. Late March-early April, depending on area and season, at first flush of new plant growth after cleaning beds, spray protective, preventative fungicides as per Extension recommendations for prevention/management of Gray Mold Fruit Rot and other diseases including Anthracnose Fruit Rot. The most active Gray Mold infection period is during bloom, re-apply sprays after every rain of 1/2" or more during bloom. If done right, you can (should) put that sprayer away during harvest, who wants to eat sprayed fruit!

15. Early April through harvest season, every week, drip irrigate as needed, or once every 5 days on our heavier soils in very hot, dry, windy weather, (much more often on sandy soils) to move water plus needed nutrients to berry plant roots. In lieu of weekly fertigations, recent NCSU research shows 3 fertigations at 3 week intervals, of 10 to 15 lbs. actual N per acre per fertigation, is as good or superior, to small, weekly spoon feeding fertigations, especially early in the fruiting season. On carry-over beds, many growers use a 1-1-1 ratio of N-P-K at these 3 week intervals in lieu of straight N fertigations, and achieve excellent results.

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