Cultural Practices

Fertilizing Herbs

Over-fertilizing herbs in containers for spring sale is a common problem this time of year. Compared to most bedding plants, herbs are lite-feeders. When the herbs are mixed with bedding plants in a greenhouse the tendency is to fertilize all plants at one rate. Try to avoid this practice.

A standard recommendation for most herbs is 100 to 150 ppm nitrogen (constant liquid feed). A routine clear watering is a good practice if the soil mix is allowed to dry.

For more information on growing herbs:

Tomato: Caution Using BotaniGard

BotaniGard has again caused injury on tomato plants in the greenhouse. BotaniGard is a bio-insecticide containing the fungus Beauvaria bassiania. Growers have reported that tomato plants sprayed with BotaniGard ES have developed dramatic edema, downward curling of the leaves and yellowing along the veins of the leaflets. Injury has been reported with the ES formulation. Less injury is likely when using the WP. BotaniGard should be applied to tomatoes in the greenhouse with caution.

Paul Lopes

Growing Easter Lilies

Easter falls on a late date in 2006 (April 16). As a result, growers will need to slow their lily crop development without sacrificing quality. Begin by using a well-drained medium to avoid root-rot and leaf yellowing later in the crop. Run a soil test before bulbs arrive, and then periodically during the crop. If leaf scorch has been a problem in the past adjust pH to 6.5 - 7.0 and do not add superphosphate. If calcium is below 100 ppm but pH is in a good range, incorporate gypsum at 2-4 lbs. per cubic yard. Start fertilizing as soon as lilies emerge and continue to within 7 days of sale.

Weed Management in Greenhouses

Before placing a crop in a greenhouse this growing season, be sure the greenhouse is free of weeds. One way to prevent weeds is to use weed block fabric on greenhouse floors. To prevent water from puddling and creating a safety hazard, start with a well-drained gravel floor. Place the weed fabric over the gravel and leave the weed fabric bare so it can be easily swept. Covering the fabric with crushed stone will make it difficult to remove spilled growing media and make an ideal environment for weeds to grow.

pH and Fertility Requirements of Spring Annuals

Providing the proper combination of pH and fertility levels for spring annuals can be quite a challenge for growers used to the traditional "one-size-fits-all" approach to fertilizing bedding plants and pH management. The summary below organizes the pH and fertility requirements of widely grown seed- and vegetatively-propagated annuals using recent BallFloraPlant®, EuroAmericanTM, and Proven Winners® catalogs. The plant culture sections of these catalogs are in very close agreement on the pH and fertility requirements for almost all of the species.

Handling Plants on Arrival

As plant material is received and handled during this busy time, here are a few guidelines to have greater successes and fewer problems.

Open and unpack the boxes immediately upon arrival and check the physical condition of the plants. Also inspect plants for root and foliar diseases and for insects and mites. Report any damage or discrepancies immediately to your supplier (most companies want to hear within 24 hours).

Inspect Incoming Plants

Pre-Season Cleanup

Hopefully, your greenhouses are now thoroughly cleaned so there is no leftover debris, organic material, weeds and "pet plants" that may serve as a source of pests and diseases plus thoroughly disinfested in preparation for the upcoming growing season.

Inspecting incoming plants

Handling Growing Media

How a mix is handled can affect the air and water content of the mix. Compaction is an important factor to consider for plant root health when handling growing media. Air space that results in good drainage can be cut in half or even eliminated by compaction. To minimize compaction, containers, cell packs and plug trays should be lightly filled and the excess brushed away. The media should not be packed down, tamped down, or the filled pots tapped down on the bench several times, and the pots and trays should not be stacked directly over one another.

Controlling Weeds

Many growers (who are growing their garden mums in outdoor fields) may have a few greenhouses empty between crops. If so, it's a good time to do a thorough clean up, including removing existing weeds (either hand pulling isolated weeds) or using a post emergence herbicide such as glyphosate that can be used in an empty greenhouse between crops as well as outside greenhouses.  However, both of these measures do not prevent reseeding of weeds. So, repair any tears in the weed block fabric or replace if needed. 

Leanne Pundt
University of Connecticut

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