Vegetable Growers News
November-December 2000, Vol. 7, No. 6
Charlie O'Dell, Extension Horticulturist
Virginia Tech
Beginning in 1998 I made several trips afield with a new digital camera for use with e-mail, seeking new ways to test the educational power of "seeing is believing". I sought to find new technology that horticultural producers developed to improve their bottom line profits for economic survival. By e-mailing the camera images to Extension Agents and their growers, more growers might be interested or motivated to change or improve a cultural practice based on seeing what was working for another grower. In the past, we've relied so much on the older concept of Extension teaching, lecture style, which often may have come across to growers as "Extension preaching" with a low rate of grower acceptance. Our success in Extension work is based on our ability to help create change so I am hopeful this new visual teaching tool will help improve our Virginia strawberry and vegetable industries by proving "a picture is worth a thousand (Extension) words".
My first digital images in this effort in September, 1998 showed how a strawberry grower, Mr. Joe Davidson of Berry Hill Farm near Clarksville in Southside, Virginia, greatly reduced costs for his strawberry plug plants. He grew them outdoors himself on his farm all the way in full sunlight without using a greenhouse. Also, by this action he sold enough plugs to other growers to help pay establishment costs for his own new acre of plastic mulched strawberries. The purchase price of finished plugs contract grown is the single biggest expense item of a plasticulture strawberry enterprise budget. By growing their own plugs from runner tips purchased from a Canadian-licensed importer of certified, disease-free Canadian-grown runner tips, as Joe did, growers can cut their plug plant costs almost in half! This was a teachable moment for me: As Extension educators, we must never assume that information flows only in one direction when working with growers! Joe's success was widely publicized appearing in American Fruit Grower and Virginia Vegetable Growers Newsletter in the fall of 1998, but not many growers have adopted this money-saving idea to date. To save $1,000. per acre in plug plant costs in year 2001, more growers may wish to review the information below.
4 Steps to Success, A New Simple, Outdoor Strawberry Plug Production System:
- In early August Joe stuck the Canadian-grown strawberry runner tips into commercially produced potting media, 50 cells/flat, using work tables placed in shade outdoors. 3" deep spear-shaped cells are fine. Media was similar to that used by tobacco producers for growing float bed tobacco transplants.
- Then he placed flats containing the freshly stuck tips directly in full sunlight outdoors on the ground on landscape fabric for drainage and weed control, under his new micro-sprinklers watering system.
- He built and installed a garden hose-operated, home water well-supplied micro-sprinkler "mini-wobblers" system. At 25 pounds psi water pressure, each mini-wobbler sprinkler used 0.56 gallons per minute. A water controller time clock was used allowing up to 20 seconds of water to be applied every 3 minutes for 10 hours from 8 AM to 8 PM for the first 5 days. Consider the low water use: 20 of the 3 minute cycles per hour X 20 seconds per cycle = 400 seconds per hour equals only 6.66 actual minutes of water use per hour. 7 minutes per hour equals only 3.92, less than 4 gallons of water per hour per sprinkler. On a 12' X 12' grid, 2 sprinkler lines were 12' apart, 6 sprinklers per lateral line were also 12' apart on each line for good watering overlap. The 12 sprinklers used only a total of 48 gallons of water per hour. The first line was placed at the outer windward edge of the plants. His main header line out to the plugs was a water hose on his first planting, later he used 1" PVC pipe for a header. His 2 lateral lines for sprinklers were of _" PVC pipe. 3' tall risers for the mini-wobbler sprinklers were of _" PVC pipe. Plastic electric fence posts driven into the ground tied to the risers were ideal for holding the risers steady in the vertical position.
- He began to harden off the plants the second week by lengthening the interval between watering, more like 30 seconds on, 10 minutes off, then gradually to 15 minutes off, adjusting the on-off cycles according to temperature, wind, cloud cover and plant needs. Frequent examination of plants and root media were used as the basis for making watering adjustments. By the third and final fourth weeks, the off-cycle was lengthened gradually to first one, then to two, then to three or longer hour off-periods between longer on-periods needed to adequately soak the rooted media. He produced compact, robust plug plants that completely rooted down to bottoms of cells in 5 days or less in full sun, that were ready to go to the field in less than 4 weeks. These plug plants were grown in place outdoors all the way in full sun in the hot, dry August of 1998 during the time we were breaking heat records in Virginia under extremely droughty conditions. Note: Under conditions of more normal rainfall patterns, growers would need to carefully scan their weather forecasts to pick a tips rooting time when little rainfall was forecast for the first 3 to 5 days following tips sticking in rooting media. Otherwise, heavy rains during those first critical days could float or blast the tips out of the cells and flats. If such rain events suddenly become imminent, placing a winter crop cover over the plug plants as a blanket should soften or break the force of hard, driving rains to help protect the newly stuck tips. Edges of such temporary covers should be weighted with 8" cinder blocks placed about every 12 linear feet going around the edges of the covers. Heavy winds often accompany such driving rains; covers should be secured against violent storms.
Plug plants field set in early September were very stocky, 100% rooted in every cell. Sunlight-induced early rooting, early crown formation and early September field planting may lead to higher berry yields the following spring in colder areas. He produced 50,000 plugs with a garden hose-operated simple system, set 1 acre of plants, then sold the 30,000 extra plants which paid for his plug plant production costs plus his new 1 acre strawberry establishment costs. Joe demonstrated a top grower example of excellent risk management!
Without ever moving the plug trays after sticking tips and placing them on the landscape fabric, watered as described, he rooted a fast crop of 50,000 plug plants, 1,000 flats, in lieu of a greenhouse or any shaded structure. His outdoor wetted area was about 80' long X 40' wide. In years 1999 and 2000 he refined the system by installing a fertigator-soluble fertilizer injector on the system to feed plants several times during the latter part of the growing period. NOTE: A backflow check valve must be installed for such use. The injector also is useful for proper injection of fungicides or other crop protectants that may be used. He developed and demonstrated a new, lower cost way for growers to produce their own plug plants that obsolete our earlier concepts. Such changes are coming so fast in technology, both from universities, from nurseries and from top growers like this. Our hats are off to Joe Davidson for deciding his idea was worth trying. He made it pay and so can you! Also, our thanks to Joe for his willingness to share such information and to answer questions and concerns of other growers who are interested in lower-cost transplant plug production, phone: 800-345-3747.
Trade names are used for information purposes only. Virginia Cooperative Extension, Virginia Polytechnic Institute and State University, and Virginia State University do not endorse those mentioned nor do they intend or imply discrimination against those not mentioned.
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