The demand for plug transplants by the Florida winter strawberry (Fragaria ×ananassa Duch.) industry may increase as water conservation during plant establishment becomes more important and the loss of methyl bromide fumigant makes the production of bare-root transplants more problematic. A study was conducted during the 1995-96 and 1996-97 seasons to determine the effect of container size and temperature conditioning on the plant growth and early season fruit yield of `Sweet Charlie' strawberry plants. Plants in containers of three sizes (75, 150, and 300 cm3) were grown in one of two temperature-controlled greenhouses (35 °C day/25 °C night or 25 °C day/15 °C night) for the 2 weeks just prior to transplanting into a fruiting field at Dover, Fla. Plants exposed to the 25/15 °C treatment had significantly higher average root dry weights at planting in 1995 and 1996 than did plants exposed to the 35/25 °C treatment. Plants exposed to the 25/15 °C treatment also had higher average fruit yields than the plants exposed to the 35/25 °C treatment (48% and 18% higher in 1995-96 and 1996-97, respectively). The effect of container size on plant growth and yield was variable. Plants propagated in the 150- and 300-cm3 containers tended to be larger (at planting) than the plants propagated in the 75-cm3 containers, but the larger container sizes did not result in consistently higher yields.
A greenhouse hydroponic system, which uses suspended plastic troughs, was found to be an efficient system for the production of high quality strawberry (Fragaria ×ananassa) plantlets. In this system micropropagated mother plants of `Oso Grande' and `Sweet Charlie' produced an average of 84 and 80 daughters per mother plant, respectively, in 1996, at a plant density of 3 mother plants/ft2 (32 mother plants/m2). Nearly 100% of the plantlets harvested from the system were successfully rooted in plug trays, and showed no symptoms of leaf or crown diseases.
Plugs are rapidly replacing fresh-dug bare-root and cold-stored frigo plants as transplants for strawberry (Fragaria × ananassa) production worldwide. Plugs have many advantages over these other types of propagules. They are grown in controlled environments (greenhouses, tunnels) in less time than field produced bare-root transplants, and are not exposed to soilborne pathogens. Plugs afford greater grower control of transplanting dates, provide mechanical transplanting opportunities and allow improved water management for transplant establishment relative to fresh bare-root plants. New uses for plugs have been identified in recent years; for example, photoperiod and temperature conditioned plugs flower and fruit earlier than traditional transplants and plugs have been used for programmed greenhouse production. Tray plants have superior cold storage characteristics relative to bare-root, waiting-bed transplants. Both fresh and frozen plugs are used in a number of indoor and outdoor growing conditions and cultural systems.
Tomatoes (Lycopersicon esculentum Mill. cv. Jet Star) seedlings grown in small cells (plugs) in trays holding 200, 406, or 648 plants per flat (28 × 55 cm) were larger after 6 weeks as cell size increased, but all were acceptable. Other seedlings, transplanted at weekly intervals from plug trays to plastic cell packs (48 cells per 28 × 55-cm flat), were of similar size during weeks 1-3; seedlings from 648-plug trays were smaller than the others by week 5-6. Seedlings from 200-plug trays planted at weekly intervals into containers where plant-plant competition was absent were larger through 6 weeks than those from 406- and 648-plug trays. Early marketable and total yields were similar for plants held in 406-plug trays 1 to 4 weeks before their transfer to 48-cell flats, but yield decreased for those held 5 to 7 weeks.
Seeds of marigold (Tagetes erects L. `Janie') were sown in flats of three cell sizes (inverted pyramids, Todd 080A, 100A, or 175; volume 7, 24, or 44 cm3, respectively) or in flats of different root cell configurations [Todd 100A, Grow-Tech (GT) 200, or Growing Systems (GS) 135; shaped as inverted pyramid, cylinder, or cylinder with a bottom lip, respectively]. During 2 consecutive years, plants grown in Todd 080A trays had 60% less leaf area and shoot and root dry weights than plants grown in Todd 175 trays. Plants grown in Todd 100A trays had 30% less leaf area and shoot and root dry weights than plants grown in the larger volume tray. Stem length was less affected by container size. The rate of shoot dry weight gain during the 3 weeks after transplanting in the field was greater in plants from the smaller containers (Todd 080A and Todd 100A) in 1987. Final height (7 weeks after planting) of plants from Todd 080A or Todd 100A flats was 12% and 7% less, respectively, than those of plants grown in Todd 175 flats, while final plant quality was reduced 34% and 21%, respectively, in plants from these flats in 1987. Similar, but smaller, effects were recorded in 1988. Container type had little effect on plant growth in the greenhouse and no effect on growth in the landscape. The maximum quality rating in the landscape, awarded to plants from Todd 100A flats, was 12% greater than that of plants from GT 200 flats in 1987 and 5% and 9% greater than plants from GT 200 and GS 135 flats, respectively, in 1988. Final plant performance of marigold seedlings was reduced more by root restriction or transplant size than previously reported with vegetable species.
control container ( Table 2 ). When grown without or with shuttle trays, plants grown in bioplastic, rice hull containers, and the sleeve required similar amounts of water to reach anthesis as those grown in the plastic control. Placing the biocontainers
until root growth is sufficient to maintain stability. To account for this, individual pocket bottoms were cut out from a shuttle/carry tray with a 1-cm lip and placed between the containers and the drain tray. Plants were grown under supplemental light
nutrient conditioning. Each individual trayplant received 50-mL nutrition solutions on a thrice-weekly basis from 10 July to 26 Aug. There were two nutrition solutions ( Table 1 ). In solution A, 30 g compound fertilizer, ‘SoluFeed’, was dissolved in 100 L
× nutrient × irrigation) were replicated four times for each species. Four flood trays were constructed for each species and one replication of each treatment combination was maintained in each flood tray. Plants were grown in an open-sided greenhouse exposed
media as subplot factors. Forty seedlings were grown in each media × fertilizer treatment combination and each irrigation treatment was replicated three times (three separate subirrigation trays). Plants were watered based on container weights as