Summary and discussion– Takeda 1999
“Out-of-Season Greenhouse Strawberry Production in Soilless Substrate”
Published 1999, Advances in Strawberry Research. Volume 18, pp 4-15.
http://www.ars.usda.gov/SP2UserFiles/Place/19310000/FTakeda/1999Advances%20in%20Strawberry%20Res%20feature.pdf (link directly to paper via Fumi’s ARS website)
Summarized by Anita (Teena) Hayden, PhD (UTK, June 2007)
About the paper and
author – Fumiomi Takeda is a researcher with the Agricultural Research
Service at the Appalachian Fruit Research Station in
of Strawberries – In other parts of the world, strawberries are more likely
to be produced under plastic than in open fields.
Rationale for Soilless Systems – Methyl bromide has been an important soil fumigant to control soilborne pathogens, insects, nematodes and weeds in field strawberries. However, with regulations restricting use of methyl bromide, various alternative methods of producing strawberries are being developed and adopted. The loss of methyl bromide will likely lead to decreased yields in field systems, opening market opportunities for greenhouse-grown strawberries. Soilless media can be used in place of soil in protected agriculture and greenhouse systems, thereby eliminating the source (soil) of many of the problems. These systems also provide an opportunity for producing out-of-season fresh strawberries when their market value is highest.
Most greenhouse systems involve growing the strawberry plants as annuals by establishing them in late summer in the greenhouse and harvesting fruit from November through January. Unfortunately, crowns are difficult to obtain during the summer months, so some research has been done on using cold-storage transplants or propagating runner tips specifically for mid- and late-summer planting. Propagating tips locally in greenhouses permits growers to produce their own propagation material on an ideal timetable as well as reducing the plants’ exposure to soil pathogens and pests.
Strawberry Production in Soilless Systems – There are two basic strategies in hydroponic systems – “closed” and “open” systems. In “closed” hydroponic systems, plants are grown in pipes or channels so the fertilizer nutrient solution can be recirculated in a “closed” loop. The solution may be supplied continuously, as in NFT (nutrient film technique) where a small amount (“film”) of the fertilizer solution flows by the roots at all times. Alternatively, the solution may be supplied intermittently in a closed system, as in “ebb and flow” or “flood and drain” systems where the plants are grown in pots and irrigated by flooding the table containing the pots. In “open” systems, fertilizer is supplied to the plants, usually through a dripper, and drains through the medium and is not recovered or recirculated. Open systems may be preferable for varieties especially susceptible to root-zone pathogens.
The timing for greenhouse production is critical in order to
compete in the marketplace.
Cultural Systems –
The author evaluated productivity of bare-root dormant, bare-root fresh-dug,
and plug plants in NFT in
Vertical hydroponic systems have also been tried for
strawberries. Vertically-hung bags and PVC pipes, as well as columns of
stacking pots are examples of vertical systems. Nutrients are applied at the
top and the solution passes through the substrate and drains from the bottom.
Note that the composition (relative concentrations) of individual fertilizer
ions can change as the solution passes through the media, so plants on the
bottom may not be getting the same fertilizer mix as those on the top. Light
distribution is also uneven in these vertical systems, and yields can be
dramatically delayed and/or reduced on the plants at the bottom of the column.
Plants at the lower level may receive only 10% of the light falling on the
uppermost plants. In winter months in the mid-Atlantic region of the
Bench-top production of strawberries has been evaluated in
Europe in the
Fruit Production – Different approaches to improving yield of winter-grown
strawberries have been investigated. It was found that plants grown from
second-order daughter plant cuttings produced similar yields than third-order
daughter plants over a three month period, although the second-order plants
produced a larger harvest in the first month of the fruiting period. Plug
plants out-performed fresh-dug, bare-root plants in all three cultivars
investigated (Sweet Charlie, Camarosa and
Another strategy investigated to manage pest and diseases was to bring plants into the greenhouse at one-month intervals and remove them after the initial cycle of fruiting, thereby staggering the cropping cycles over the 6 to 8 month production period.
Conclusion – goals of a successful system include maximizing profitability with minimum energy inputs, minimal maintenance, high yields of high-quality fruits during the highest value season, high plant density and minimal or no need for pesticide applications. High capital costs and skills are needed for hydroponic systems, and the currently available strawberry cultivars need further R&D for adaptation to greenhouse winter production systems.