INCENTIVES TO JOIN VERMONT VEGETABLE AND BERRY GROWERS ASSN.

In a fit of rational exuberance, the Association’s Board of Directors is offering first-time memberships in the Association at half price for 2003! That’s just $16 for the benefits of camaraderie, an Agriview subscription, a New England Extension Vegetable or Small Fruit Management Guide, eligibility for farm research grants, and much more.  Also new for 2003 is the On-Line Marketing Guide, where each member farm has a web page describing their products, markets and other information, including logos and pictures. A state-wide, searchable listing is in the works. For a membership application and more details click on ‘Association of Growers’ at www.uvm.edu/vtvegandberry or give Doug Johnstone a call at 802-885-2985.

SOLUBLE SALTS IN COMPOST

High levels of soluble salts can damage plants and inhibit seed germination. Soluble salts are of more concern in potting soils and greenhouse uses than in the field where compost applications are diluted by mixing with soil and where salts tend to leach with rainfall. The soluble salt level, as measured by conductivity, in finished compost generally ranges from 1 to 30 dS/m (decisiemens per cubic meter, which is equivalent to other units of measure: mS/c, ECe or mmho/cm, all of which represent electrical conductivity). For field use, a level of 5 dS/m or less is ideal, but compost is often twice that high in salt. Levels of 10 dS/m should not be a concern if compost is thoroughly incorporated and mixed with soil. However, problems may occur if high-salt compost is applied directly before or to a salt-sensitive crop like bean, carrot, strawberry or onion. For most crops, the ultimate conductivity of soil in the field should be below 2 dS/m and for potting mixes conductivity should be below 3 dS/m. Mixes tend to be higher in soluble salts because they contain more compost and/or soluble nutrients than field soil. For more information on making quality compost order the Field Guide to On-Farm Composting published by NRAES, 152 Riley Robb Hall, Ithaca NY 14853. It’s available from my office for $14 postpaid.

REMINDER: TEST YOUR COMPOST BASED POTTING MIX

It’s a good idea to test BEFORE you sow lots of seed if you are using a compost-based organic potting soil or a ‘homemade’ mix for bedding plant or transplant production. Send a full quart of mix to the UVM Agricultural Testing Lab, Hills Building, Burlington VT 05405-0082 and ask for the ‘saturated media test’. Unlike a regular soil test that uses a weak acid to extract nutrients before measuring them, this test uses water as an extract so it measures immediately available nutrients, and unlike the regular field soil test your results will include nitrate and conductivity (soluble salts), as well as pH and usual list of macro nutrients. Include a $15 check payable to UVM.. In addition to a lab test, it is advisable to make test plantings of sensitive, fast growing crops such as cress and oats as early as possible.

NEW ENGLAND FARMERS' DIRECT MARKETING CONFERENCE MARCH 12-13

Change, Challenge and Collaboration is the theme of the 2003 New England Farmers' Direct Marketing Conference, to be held March 12-13 at the Holiday Inn Boxborough Woods, Boxborough, Mass. Two featured speakers, Pete Luckett and Jim Cain, will each give a full-day workshop on March 12.  Luckett is one of Canada's leading independent green grocers. His workshop is titled "Creating the WOW Every Day!" Cain, has taught adventure-based team building for more than 25 years. His workshop, "A day of teamwork and teamplay," will help attendees transform their employee hiring and training practices. The conference sessions on March 13 are "Collaborating with those who sell New England," "Selling your farm by selling New England," "What flew & what flopped," and "Understanding the media: A panel discussion." The workshops on March 12 are $85 per person if pre-registered by March 3. Late or on-site registration will be $100. Conference registration for March 13 is $75 ($95 if late or on-site) and includes coffee, lunch, and evening social. For information, call (413) 529-9100, e-mail info@massfarmstands.com, or visit www.newenglandconference.com.

SUPPLEMENTAL LIGHTING PRIMER (from a variety of web sources)

A variety of artificial lighting is available to supplement natural sunlight for plant growth. It's important to set up an adequate and cost effective lighting system, and to understand the pros and cons of different types of lights available.

Fluorescent lights are fine for starting seedlings but not for growth and flowering. Their low heat output allows them to be just inches away from plants but their low intensity is inadequate for plant growth beyond the seedling stage. Most plants will grow just as well under cool white fluorescent lights as under more expensive blue-red fluorescent ‘grow lights’. Cool white fluorescent lights and fixture are relatively inexpensive, and many growers use lots of them in ‘growth chambers’ designed to hold many seedling trays that later get set out in natural light in the greenhouse or field. To ‘grow on’ larger plants with winter sunlight or indoors requires a more intense source of supplemental light, such as High Intensity Discharge (HID).

HID lamps generate light by passing electricity through gas under high pressure, unlike fluorescent bulbs that utilize low-pressure gases, and standard incandescent bulbs that pass current through a wire filament. For HID bulbs, the gas in the tube and the coating on the bulb determine the spectrum of light emitted. HID lights require special ballasts (transformers and capacitors) and sockets to operate. Line voltage, operating characteristics, and physical shape are unique to each lamp. Never mix and match ballasts with lamps.  HID lamps include Metal Halide (MH) and High-Pressure Sodium (HPS) lights.

MH lights are the best single source for indoor growing. Standard MH lamps produce light from the blue end of the spectrum. "Corrected" MH bulbs, however, produce balanced spectrum light that contains both the red and blue wavelengths plants need for rapid growth. In a room with no outside light, it’s best to grow plants under MH lights until the vegetative growth stage is over.

HPS lamps provide an efficient light source as they put out a lot of lumens per watt. HPS light emits mainly in the red and orange region of the spectrum, and promotes excellent fruit and flower production. The lack of blue spectrum light can cause plants to become "leggy" if used alone during the vegetative stages of a plant. Growers may start plants under MH lighting, and then switch to HPS for fruit and flower development. HPS lighting is also good for extending the photoperiod in a greenhouse. Conversion bulbs are available that allow you to switch between MH and HPS bulbs using the same ballast.

It’s important to replace HID bulbs after 12 to 18 months of use. HID lamps will continue to light after that, but they will have lost a lot of their lumen output while consuming the same amount of electricity. These lamps contain some harmful materials so don't throw them in the trash. Many municipalities have disposal programs to accept HID bulbs and other hazardous materials.

Tungsten Halogen, Iodine Quartz, or Bromine lamps are similar to incandescents, as they emit the far-red end of the spectrum and are relatively expensive to operate with low lumen- to-watt output. While they may be less expensive to buy since they run on standard 110-volt current and don't require a ballast, they're a poor choice for indoor growing.

Low Pressure Sodium (LPS) are available most often in low wattages. Their lumen-to-watt output is the highest of any lamp, but they function on a very narrow band on the yellow color spectrum so they are of limited use for growing plants. LPS lights maintain their lumen output throughout their life but must be used, if at all, with an MH lamp to stimulate photosynthesis.

FUNGUS GNAT REFRESHER
(adapted from UConn Extension: http://www.hort.uconn.edu/ipm/greenhs/htms/fngnatser.htm )

The fungus gnat's life cycle from egg to adult may be completed in as little as three to four weeks depending on temperature. Eggs are laid in cracks and crevices in the media surface and mature in four to six days. Fungus gnat larvae feed and develop for about two weeks at 72 degrees. Pupation occurs in the soil. After four to five days, adults emerge. Adults are attracted to newly planted crops. Overlapping and continuous generations make control difficult.

Fungus gnat management includes good cultural practices. Thoroughly clean the greenhouse before introducing new crops. Dry, level, weed-free, well-drained floors will help to eliminate breeding areas. Keep compost piles away from the greenhouse and clean up any spilled media on the floor.

Adults are attracted to mixes with high microbial activity. Avoid using mixes with immature composts less than one year old. However, no potting mix is completely immune to fungus gnat infestations. Although mixes with coconut coir were first thought to help discourage fungus gnats, research has found high numbers of larvae in a mix containing only coconut coir, as well. Because fungus gnats like moisture, they may find a favorable environment in poorly drained media that stays wet. How it is handled may be more important than the type of mix used. If the mix is stored outside and stays moist, it may support more fungus gnat activity. Store the media so that it stays dry.

Monitoring is especially crucial when biological control or insect growth regulator use is planned. Yellow sticky cards, placed vertically at the soil surface, can be used to detect adults. Check and change the cards weekly to determine population trends. Use potato plugs at least one inch in diameter on the soil surface to monitor for larvae. Place the plug so there is contact with the media to ensure that the potato plug does not dry out. To look for larvae, first check the growing media under the plug and then the surface of the potato itself. To better time treatments, use the potato plugs to determine when larvae are present. You may see larvae on the potato plug in as little as one to three days. Be sure to mark where you place the plugs, so you can easily find them! If not removed, potato chunks can "melt out," sprout or be fed on by mice.

Bacillus thuringiensis (Bt) var. israelensis, sold under the trade name of Gnatrol, is most effective against the young larvae when they are actively feeding. The bacteria must be ingested by the larva, after which a toxic protein crystal is released into the insect's gut. The larva stops feeding and dies. Gnatrol is only toxic to larvae for two days. Repeat applications, i.e. two applications at high rates, may be needed. Steinernema feltiae is an insect-killing nematode that can be also applied as a drench treatment. The nematodes search for fungus gnat larvae. After entering the insect through various openings, the nematodes release a bacterium whose toxin kills the larvae.

A small, soil-dwelling predatory mite, Hypoaspis miles, feeds on fungus gnat larvae. It is shipped in sawdust with bran mites (a food source). The sawdust can be distributed over the media surface, especially when pots are placed close together. The mites, which may feed on thrips pupae, are best used when fungus gnat populations are low. Hypoaspis is compatible with B. t. and S. feltiae.

A variety of insect growth regulators (IGR) are registered for use on fungus gnats, such as Adept, Azatin XL, Citation 75WP, Enstar II, Precision and Pyrigro. They are most effective against the young developing larvae and will have no direct activity against adults.

(mention of pesticides is for information purposes only. No endorsement is intended nor is discrimination against  products not listed. Always read and follow the label.)