Floriculture Greenhouse Update

Fall mums will exhibit signs of wilting during extended periods of 90 plus degree temperatures. The solution may not be as easy as turning on the irrigation.Fall mums wilt when the soil is dry, but wilting will also occur in hot weather which may cause plants to be stressed, or if the roots are damage from a root disease such as Pythium, even if the soil is saturated with water. When the roots stop functioning normally the plants will show signs of stress by wilting.

Keep in mind fall mums can survive excess amounts of fertilizer and resulting soluble salts when temperatures are normal and soil moisture is maintained. Problems occur when the growing medium is dry and the salts become more concentrated, resulting in root damage. The plants will react first by wilting and than collapsing.

Take precautions to avoid overwater garden mums especially during periods of hot weather like this week.  Lift the pots and check the roots periodically. If the pots feel heavy and the soil is saturated, do not irrigate, even if it is hot. However, do not allow plants to dry to wilt prior to watering.

If plants are wilting on a regular basis and excess amounts of fertilizer have been used, the roots maybe damaged and root disease will occur. Check the plant roots, especially with slower growing varieties. The roots tell a lot about a plants health, often before the top growth shows symptoms.

Paul Lopes, Tina SmithUniversity of Massachusetts Extension

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Fall mums will exhibit signs of wilting during extended periods of 90 plus degree temperatures. The solution may not be as easy as turning on the irrigation.

Fall mums wilt when the soil is dry, but wilting will also occur in hot weather when the soil is saturated with water, and/or if the roots are damage from a root disease such as pythium. When the roots stop functioning normally the plants will show signs of stress.

Keep in mind fall mums can survive excess amounts of fertilizer and resulting soluble salts when temperatures are normal and soil moisture is maintained. Problems occur when the growing medium is dry and the salts become more concentrated, resulting in root damage. The plants will react first by wilting and than collapsing.

Take precautions to avoid overwater garden mums especially during periods of hot weather like this week.  Lift the pots and check the roots periodically. If the pots feel heavy and the soil is saturated, do not irrigate, even if it is hot. However, do not allow plants to dry to wilt prior to watering. If plants are allowed to wilt on a regular basis when controlled release fertilizer is used, the roots may burn and root disease will occur. Check the plant roots, especially slower growing varieties. The roots tell a lot about plant health, many times before the top growth shows symptoms.

Viburnum leaf beetles are becoming active in nurseries and retail garden centers. See information and photos: Viburnum Leaf Beetle UMass and Cornell

High temperature is one of the most important factors to control in the retail yard. Shading and air movement are ways to help keep temperatures cooler for plants in the retail setting. The use of 50% shade of the midday sunlight will reduce light to appropriate levels. See the fact sheet Caring for plants in retail settings: 

Two-spotted spider mites are showing up on Ipomoea. See message and photos on managing mites.

Spittlebugs: The white foam from spittlebugs can be seen now on many perennials as the spittlebugs move in from grassy areas. Most of the damage is cosmetic only and does not harm the plant. If the infestation is small, either handpick the spittle masses with a gloved hand or use a forceful jet of water to dislodge the nymphs. For more information and photo see this previous message.

Plant nutrition: Bedding plants in retail yards may be showing signs of lack of feed. With the recent prolonged high temperatures and frequent watering, fertilizer may have leached out. If new growth is yellowing and roots are healthy, fertilize with 200 ppm of a complete fertilizer such as 20-10-20 at every watering. Bedding plants usually recover easily because they are quickly purchased, and are planted out in the garden, fertilized and have room to grow.

Hanging baskets and patio pots are a different story. Plants in hanging baskets and planters will stay in those containers throughout the summer. The small volume of soil in a container is the only available source of nutrients for the plant compared to the much larger volume of soil available to the plants in a garden. Frequent watering causes much of the fertilizer to be leached out. If hanging baskets and planters are not fertilized in the retail sales area, or if controlled-release fertilizer was not used, all the fertilizer will leach out by the time the consumer buys the plants. The plants will quickly decline in quality once the customer takes the basket home. There are solutions. One is to fertilize baskets and planters in the retail sales area, on a weekly basis, using 400 ppm N, or using 200 ppm N at every watering. Another solution is to top-dress the basket or planter with a controlled- release fertilizer using 3-5 grams of N of a shorter term, 4-6 month material or use tablets according to directions. Retailers should communicate with their wholesale growers to make sure controlled-release fertilizer has not already been applied prior to shipping before fertilizing plants.

Tomato plants: Monitor for late blight and bacterial canker. See message.

Garden Mums should be planted as soon as possible upon arrival. See the message  about early season care including fertilizing and crown buds.

Tina Smith, University of MassachusettsLeanne Pundt, University of ConnecticutPaul Lopes, University of Massachusetts

Mum cuttings are arriving at some growers. Begin the season by reviewing your fertilizer program and teaching new employees to recognize Chrysanthemum white rust symptoms.

Mums are heavy feeders during the first few weeks. Growers use a variety of ways to fertilize mums. Some growers use 100% water soluble fertilizer through a drip system, some use 100% controlled-release fertilizer and some use a combination of water soluble and controlled-release. Regardless of the program you use, start plants off right and prevent premature buds by:

Using moistened soil when potting up plants, then water-in freshly planted cuttings with a fertilizer solution. Many growers are successfully using 200 to 300 ppm of 20-20-20 immediately after planting. The cuttings establish faster and grow more rapidly.

Do not stress the young plants during their first 4 to 5 weeks of growth, and especially during the first 10 days of the crop or plants will develop buds prematurely and plants will be short. Keep plants moist, well fertilized and properly spaced.

Also check plant roots regularly to monitor plant health.

To encourage soft growth that branches freely, many growers use 250-300 ppm 20-20-20 or a fertilizer that is at least 60% ammonical nitrogen as a constant feed during the first 2-3 weeks for all fertilizer programs. Then, growers using 100% water soluble fertilizer throughout the season, switch to 200-250 ppm 20-10-20 constant feed for 3-4 applications and then rotate to a calcium nitrate based fertilizer such as 15-0-15 for 1 application, then repeat. The 20-10-20 contains less ammonical nitrogen. Once plants start to show color, fertilizer is reduced to 100 ppm constant feed.

If using controlled-release fertilizer, keep in mind that the rate of release is affected by its formulation (rate of release), soil temperature and frequency of irrigation. Most formulations release at temperatures of 70°F or above, therefore during cool temperatures, fertilizer is going to be slow to release. We often have cool temperatures in June when plants need the most fertilizer. This is the reason liquid feed becomes important, to get plants growing and create vegetative growth.

Garden mums initiate flower buds easily and develop rapidly if plants are stressed in any way. If terminal flower buds are observed when cuttings arrive, plants should still perform satisfactorily. When cuttings with terminal flower buds are planted, they should be pinched hard (allow 4-5 leaves to remain) when they are turgid (4-5 days after planting). This will force out lower breaks which tend to be more vegetative. If both terminal and lateral buds have developed when cuttings arrive, it is best not to plant them, as they most likely will not perform satisfactorily.

Tina Smith, University of Massachusetts

For more information see:

Fact Sheet: Garden Mums for Fall Sales. University of MassachusettsFact Sheet 2008: Chrysanthemum White Rust. University of Massachusetts.Grolink: Belgian Mum Cultural Information Fact Sheet. Garden Mums from Cell Paks. Griffin Greenhouse Supply Company.

Monitor for Downy Mildew. See previously posted message on Downy Mildew.

Thrips populations are increasing with the warmer temperatures. Monitor for thrips using yellow sticky cards and monitor plants for Impatiens necrotic spot virus. See the message Thrips and Tospoviruses

Iron deficiency symptoms are showing up on crops. Symptoms appear as an interveinal chlorosis, normally starting at the shoot tips, but often they occur throughout the entire plant. Sometimes the leaves of iron deficient plants turn almost white. Bacopa, calibrachoa, scaevola, snapdragons, and petunia are crops susceptible to iron deficiency. Preventing iron deficiency can be accomplished by controlling pH and using an iron chelate fertilizer. Before applying iron, check the plants roots to be sure they are healthy. Unhealthy roots will result in yellow, stunted plants that may be confused with iron deficiency. See Preventing Iron Deficiency and Selecting which iron chelate to use.

Late Blight reminder to retailers: Buy and sell only tomato plants that have been started and grown here in the northeast. Tomato growers and home gardeners will be very appreciative if you do not bring late blight into New England. Late blight is a very destructive and very infectious disease that killed tomato and potato plants in gardens and on commercial farms throughout the eastern U.S. during 2009. Please do your part to prevent this disease! For information and photos on late blight, see the message: Garden Retailers and Late Blight

Tina Smith, University of MassachusettsLeanne Pundt, University of Connecticut

Tomato seedlings are for the most part, easy to grow, but every so often a problem will arise. Distorted leaves and aborted growing tips can often be explained away with evidence of herbicide use in or nearby a greenhouse or a virus originating from the seed. In this case excess fertilizing is more likely the cause.

The problem developed in a growers greenhouse affecting 90% of the crop. The tomato seedlings were in 12 inch patio pots, 3 plants in each pot. A soil test was completed on the soilless mix and the results indicated soluble salt levels of 3.04 mS/cm, an ammonium nitrogen level of 46 ppm and a sodium level of 101.2 ppm.

Tomatoes in general can tolerate high salts and high ammonium levels but tomato seedling 3 to 4 weeks old can be damaged. Leaching the soil with clear water and changing the fertilizer to a higher nitrate form is the recommendation but the plants will need to be watched to see if the new growth will return to normal.

Photo: Tomato Seedling with Symptoms

Paul Lopes, University of Massachusetts

Check the pH of growing media to adjust pH if necessary. Zonal geranium, American marigold, and all types of impatiens are susceptible to iron/manganese toxicity, a nutritional disorder associated with low growing medium pH. Symptoms show as speckling (numerous very small brown spots) on the leaves of geraniums and marigolds, usually beginning on the edges. Maintain the pH within the range of 6.0-6.6 to prevent toxicity. If the pH drops below this range, the risk for toxicity increases because at low pH too much iron and manganese becomes available to the plants. Note that ivy geraniums require a lower pH (5.5-6.0) and more iron than zonal geraniums.

Common causes of iron/manganese toxicity include: acidic growing medium pH, use of acid-forming fertilizers (e.g., 20-10-20, 15-6-17, 15-15-15), inappropriate use of acid injection, and unnecessary use of supplemental micronutrient fertilizers. Watering with acidified water and fertilizing with iron chelates benefit plants like petunia and calibrachoa, but are not recommended and will cause problems on species sensitive to low pH and iron toxicity.   

Preventing iron/manganese toxicity starts with adequate liming of the growing medium to the pH range of 6.0-6.6 before planting. "High" pH reduces the availability of iron and manganese. After planting, fertilizers with low potential acidity (e.g.,Cal-Mag 15-5-15, 15-5-25, 15-0-15) should be applied to susceptible species to raise or maintain desirable pH. Regular pH monitoring should be done and, if necessary, liquid limestone can be used to raise the pH of the growing medium. Many geranium growers treat their plants with liquid limestone as a routine preventive treatment. The label for Cleary's Limestone F suggests using a 100:1 injector to dilute and apply 1 gallon of product. Two applications of 2 qt./100 gal. flowable lime applied 1 week apart has a similar effect to a single drench with 4 qt./100 gal. The effectiveness of liquid limestone depends on the volume applied/depth the solution reaches. Foliage should be rinsed after the liquid limestone is applied to remove any residue.   

Research at North Carolina State University indicated that there are three possible causes for the sudden pH decline associated with micronutrient toxicities. The causes are phosphorus deficiency, high production temperature and high light intensity. For more information see the recently published article: Sudden Substrate pH Decline (PDF).

Photos: Iron and manganese toxicity on geraniums Iron and manganese toxicity on marigolds

Fact Sheets: "Iron Out (PDF)" and "Managing the pH of Container Media" (PDF) University of New Hampshire "pH and Fertility Review for Vegetatively Propagated Annuals" University of Massachusetts

Douglas Cox, University of Massachusetts Leanne Pundt, University of Connecticut Tina Smith, University of Massachusetts

Allow newly arrived pre-finished plants to recover from shipping stress and to initiate active root growth (about 1-2 weeks) prior to transplanting into the final-sized pot. Hydrangea blooms are formed on the previous year's growth, so the flowers are already in place in the dormant buds. The ideal starting temperature for hydrangeas is a 60 to 62°F soil temperature supplied with bottom heat, while maintaining slightly cooler air temperatures (about 58°F). This allows root activity prior to bud opening on the shoots. Grow plants slightly on the "dry side" prior to transplanting to prevent root rot and to encourage root development. Avoid fertilizing until root activity has occurred.

One of the main problems with hydrangeas is poor root establishment which leads to water stress during late stages of forcing. To prevent this, several sources recommend slitting the root ball to form an X, when transplanting, opening the sections and placing in direct contact with the growing media in the pot.

To ensure clear pink or blue inflorescences, order cultivars programmed for the desired color and continue the color program throughout forcing. Fertilization practices during the previous summer growth phase influences coloration during forcing, and changing the color program during the forcing phase can result in shades of mauve tones.

Whether a hydrangea (excluding white cultivars) develops a pink or blue inflorescence is dependent on the presence and availability of aluminum. The absence of aluminum assures pink flowers; high availability of aluminum leads to blue flowers. By regulating aluminum, flower color can be controlled.

Pink Flowers Avoid supplying aluminum to plants and use fertilizers that do not contain aluminum. Use relatively high levels of phosphorus in the fertilizer program. Phosphorus antagonizes aluminum uptake and helps assure pink flowers. Rotating mono-ammonium phosphate (11-53-00) into the feed program will help raise phosphorus levels and help prevent aluminum uptake. An example feed program would be continuous feeding using 150 ppm nitrogen from 20-10-20 (10 oz/100 gal) rotated with 100 ppm nitrogen from 11-53-00 (18 oz/100 gal) every third feeding.

Try to maintain a substrate solution pH of 6.0 to 6.2; aluminum becomes more available at lower pH's. Be careful not to allow the pH to rise much above 6.4, or iron deficiency chlorosis will become a problem. Supply low to moderate levels of potassium. High levels of potassium tend to increase bluing of hydrangeas.

Blue Flowers Although dormant plants purchased as blues will have received aluminum sulfate prior to shipment, aluminum must also be supplied during the forcing period. Start drenching with aluminum sulfate immediately after transplanting. Apply 8 fl oz of drench per 6 inch pot using 10 lb aluminum sulfate per 100 gallons of water. Drenches should be applied to moist substrates only as drenching dry soil will result in damaged roots. Make applications at 10 to 14 day intervals. About 10 days after each application, measure the pH of the substrate. If the pH is higher than 5.6, another application of aluminum sulfate should be made. Continue this procedure throughout forcing. The aluminum sulfate not only supplies aluminum, it also maintains a low (5.2 to 5.5) pH in the substrate solution, desirable during forcing of blue hydrangeas. Use a phosphorus-free substrate for transplanting and use a fertilizer lacking phosphorus. Apply high levels of potassium for increased bluing. For example, apply 150 -200 ppm 21-0-0 nitrogen and 300 - 350  ppm 13-0-44 potassium at each irrigation.

Terminate fertilizer when flower buds begin to show color to increase the postharvest life of the flowers.

For more information

Commercial Hydrangea Forcing (PDF)by Douglas A. Bailey, North Carolina State University.

FloriCAST (short video) on fertilizing florist hydrangeas by Kimberly Williams, Kansas State University

Tina Smith, University of Massachusetts

An injector setting of 1:100 means that 1 gallon of fertilizer concentrate makes 100 gallons of final solution. It does not mean that the injector is delivering 100 parts per million (ppm) nitrogen. Many injectors have a dual settings, in percent and ratio. A 1 percent setting is the same as a 1:100 ratio, a 2 percent setting is the same as a 1:50 ratio and a 0.5 percent setting is the same as a 1:200 ratio. To make the appropriate concentrate for a specific injector setting, determine the amount of fertilizer to dissolve per gallon of water. This can be done by using a chart or calculating it yourself.  Note that fertilizer should be measured by weight for mixing, not volume. Also, fertilizer solution color is not a reliable gauge for fertilizer concentration.

For an easy to use table on injector ratios, ppm Nitrogen and fertilizer calculations see: Injector Ratio Table (PDF)

To learn more about how to calculate fertilizer ppm for greenhouse crops see: Fertilizer Calculation Fact Sheet

Fertilizer injectors should be checked periodically to be sure they are operating accurately.  This can be done by testing the electrical conductivity (EC) of the fertilizer solution. To check a fertilizer solution, use a good conductivity meter or send a sample to your State University soil test laboratory.

Procedure to check the EC of a fertilizer solution:

1. Let plain water (no fertilizer) run a little, then collect water in a clean bucket. Take a sample of the plain water from the bucket. Check the EC of the untreated water supply.
2. Mix up your fertilizer as you normally do and run it through the injector and hose. Let it run a little to be sure you get an accurate sample. Take a sample of the fertilizer-injected water from the end of the hose and use your meter or soil test laboratory to check the EC of the sample.
3. Subract the EC value of the untreated water from the EC value of the fertilizer water.
4. Compare the results to an EC chart from the fertilizer manufacturer or fertilizer bag. The chart will correlate the EC measurement with the ppm Nitrogen so you can determine if your injector and mixing procedure is accurate.

Soil Testing Laboratories

University of Massachusetts Soil and Tissue Testing Laboratory University of Connecticut Soil Nutrient Analysis Laboratory

Tina Smith, University of Massachusetts

It is a good time to conduct a soil test and review your fertilizer program for your garden mums. Be sure adequate fertilizer is applied especially with recent rainy weather and if controlled release fertilizer is the only source of feed. Six to seven weeks after the cuttings were planted until the flowering plants are sold, feed levels can be reduced to 150 to 200 ppm twice weekly (depending on weather) until color, or even go bi-weekly with a Cal-Mag type feed. This will maintain foliage color without creating excess growth before flowering. Fertilization should be continued at least until the buds are just starting to show flower color.

For more information see the article on fertilizing on the Yoder website: Yoder

Here is a listing of the laboratories in Massachusetts, Connecticut and Rhode Island where growers can send samples.

Massachusetts University of Massachusetts, Amherst Soil and Plant Tissue Testing Laboratory http://www.umass.edu/plsoils/soiltest

University of Massachustts, Amherst Extension Plant Diagnostic Laboratoryhttp://www.umass.edu/agland/diagnostics/

Connecticut University of Connecticut Soil Nutrient Analysis Laboratory http://www.soiltest.uconn.edu Disease Diagnostics, Soil Testing Connecticut Agricultural Experiment Station http://www.caes.state.ct.us

Rhode Island University of Rhode Island Plant Clinic Phone: 1-401-874-2750

Tina Smith, University of Massachusetts

Many growers will be potting up garden mums and it's a good time to revisit your fertilizer program. Mums are heavy feeders during the first few weeks. After flowers are formed, nutrient demand diminishes. Your fertilizer program and fertilizer selection should be based on irrigation water quality, so have your irrigation water tested if it hasn't been done and conduct regular soil tests to monitor soil fertility.

There are several ways to fertilize mums. Some growers use 100% water soluble fertilizer through a drip system, some use 100% controlled-release fertilizer and some use a combination of water soluble and controlled-release. To start plants off right and prevent premature buds:

Use moistened soil when potting up plants, then water-in freshly planted cuttings with a fertilizer solution containing 200 to 300 ppm of 20-20-20 immediately after planting. The cuttings will establish faster and grow more rapidly.

Do not stress the young plants during their first 4 to 5 weeks of growth, especially during the first 10 days of the crop. Keep plants moist, well fertilized and properly spaced.

Check plant roots regularly to monitor plant health.

To encourage soft growth that branches freely, use 250-300 ppm 20-20-20 or a fertilizer that is at least 60% ammonical nitrogen as a constant feed during the first 2-3 weeks for all fertilizer programs. If using controlled-release fertilizer, keep in mind that its rate of release is affected by its formulation (rate of release), soil temperature and frequency of irrigation. Most formulations release at temperatures of 70°F or above, therefore during cold temperatures of late spring/early summer temperatures, fertilizer is going to be slow to release, when plants need the most fertilizer. This is why liquid feedings become important, to get plants moving and create vegetative growth. Liquid feeds of at least 60% ammonia forms of nitrogen, combined with no water stress, are important to minimize premature budding!

Examples of Fertilizer Programs for Garden Mums

100% Water Soluble Fertilizer Using Drip Irrigation After plants are established using 20-20-20 the first few weeks, switch to 200-250 ppm of 20-10-20 constant feed for 3-4 applications and then rotate to a calcium nitrate based fertilizer such as 15-0-15 for 1 application, then repeat. Once plants start to show color, reduce to 100 ppm constant feed.

Combination of Water Soluble Fertilizer and Low Rate of Controlled Release Fertilizer Use 250 ppm of 20-20-20 at time of planting and constant feed for first two weeks  then change to 20-10-20, 300 ppm once per week and use clear water from first color until sale.

More information is available from:

Yoder 

Garden Mums from Cell Packs (PDF)

Tina Smith, University of Massachusetts

Many growers are performing their own soil tests for pH and soluble salts on-site. Others are sending samples to different labs for their soil tests and some do a little of both. Often growers end up with a confusing collection of tests done different ways with widely different "numbers".

There are three commonly used methods of testing soilless media based on the use of water as an extracting solution. They are: saturated media extract, 1:2 dilution method, and leachate pourthru. The number representing the level of soluble salts from a soil test using a 1:2 dilution method are going to mean something different than results from saturated media extract (SME) or leachate pourthru. For example, 2.6 would be "extreme" (too high) for the 1:2 method, "normal" for SME, and "low" for leachate pourthru. Always use the interpretative data for the specific soil testing method used or otherwise you could make an incorrect interpretation of the results. The differences in pH results between the tests is much smaller.

The major difference between the current methods of greenhouse media testing is the way plant-available nutrients and soluble salts are "extracted" from the media samples for analysis. Differences between the actual methods of pH, soluble salts, and nutrient analysis and the laboratory equipment used to do the analyses are not as important as how the plant-available nutrients are extracted from the sample.

When people think of "soil testing", they might imagine some procedure which analyses the solids in a mix for pH, nutrients, and soluble salts. However soil samples themselves are not actually analyzed during a soil test, but rather plant-available nutrients are pulled out or "extracted" from the sample using an "extracting solution".

For more information on the three different methods for testing soil , proper sampling and a comparison table with soluable salt levels for each of the methods, see the fact sheet:

Current Methods of Greenhouse Media Soil Testing and How They Differ

Tina Smith

A common problem often diagnosed this time of year with spring crops is excess soluble salts. Generally, this is a result of too much fertilizer in relation to the plants needs. Inadequate watering or leaching, or poor drainage can also result in high soluble salts.

Sometimes high soluble salts levels occur when root function is impaired by disease or physical damage. Always check the condition of the root system when trying to diagnosis a problem.

Seedlings, young transplants, and plants growing in media containing 20% or more field soil are less tolerant of excess soluble salts.

Injury to bedding plants from excess salts seems to be most common shortly after transplanting. Seedlings are much less tolerant of salinity than established, rapidly growing plants. Small or slow-growing seedlings (e.g., begonia, petunia), poor quality seedlings, and rooted cuttings of New Guinea impatiens are easily harmed by excess salts.

Some soilless mixes may contain enough "starter charge" to cause excess salts problems in the first few weeks after transplanting, particularly when a water-soluble fertilizer is also applied

If you suspect you have a problem with excess soluble salts, the container/soil should be leached twice with clear water.

Paul Lopes

Tobacco Mosaic Virus (TMV) symptoms should not be confused with symptoms caused by iron deficiency. Iron deficiency symptoms generally show up as an interveinal chlorosis, normally starting at the shoot tips, but often they occur throughout the entire plant. Sometimes the leaves of iron deficient plants turn almost white. Symptoms of TMV show yellow and green mottling, upward leaf curling, leaf distortion and overall stunting. Bacopa, calibrachoa, scaevola, snapdragons, and petunia are crops susceptible to iron deficiency. Preventing iron deficiency can be accomplished by controlling pH and using an iron chelate fertilizer.pH control. Acid pH favors the availability of iron to plants, therefore the target pH range for crops susceptible to iron deficiency is fairly low, 5.5 to 5.8. Most commercial soilless media have pHs in this range to start and the use of an acid-forming fertilizer (e.g., 20-10-20, 15-16-17, 15-15-15) may be enough to keep the pH in this range. 21-7-7 Acid Special fertilizer is effective at quickly lowering pH, but it should not be used more than once or twice to fertilize bedding plants and other annuals. If plants are irrigated with high alkalinity water then iron chelate fertilizer or acid injection should be considered. If a grower mixes his/her own sphagnum peat-based growth medium dolomitic limestone should be added at a rate of no more than 5lbs./yd. Too much limestone is an aggravating factor contributing to iron deficiency. Iron Chelate. Fertilizing sensitive crops with iron chelate fertilizer from time to time is probably the least complicated way of preventing iron deficiency. Most greenhouse supply companies carry Sprint 330 (10% iron), Sprint 138 (6% iron), or similar iron chelate products. Sprint 138, however, is the preferred chelate because it maintains iron availability over the widest pH range. Sprint is generally applied as a soil drench at the rate of 8 oz./100 gal.(½-¾ tsp. per gallon). At this rate, iron chelate can be applied every 3 or 4 weeks if desired. Iron chelate can also be mixed as a concentrated solution for injection or low rates can be mixed and injected with other fertilizers. Note that some growers have replaced a separate iron chelate fertilizer with a commercially available, all in one, “petunia� fertilizer that contains chelated iron.

Do not use fertilizers containing chelated iron on iron sensitive crops such as geraniums, marigolds and other crops that are sensitive to iron and exhibit iron toxicity symptoms. To review pH and fertility needs of spring crops see information below.

Photos: Symptoms of Iron Deficiency on Petunias, 2, 3 More Photos of iron deficiency Photos: Symptoms of TMV on calibrachoa, 2 Fact Sheets: Preventing Iron Deficiency, pH and Fertility Review for Vegetatively Propagated Annuals Soil Testing and Disease Diagnostic Labs

Doug Cox and Tina Smith, University of Massachusetts

Prevention and correct identification of insect, diseases and nutritional problems can help you save money by reducing crop losses, improve the quality and marketability of your crops and prevent the application of the "incorrect" pesticide or fertilizer.

Here is a listing of the laboratories in Massachusetts, Connecticut and Rhode Island.

Massachusetts University of Massachusetts, Amherst Soil and Plant Tissue Testing Laboratory http://www.umass.edu/plsoils/soiltest

University of Massachustts, Amherst Extension Plant Diagnostic Laboratory http://www.umass.edu/agland/diagnostics/

Connecticut University of Connecticut Soil Nutrient Analysis Laboratory http://www.soiltest.uconn.edu Disease Diagnostics, Soil Testing Connecticut Agricultural Experiment Station http://www.caes.state.ct.us

Rhode Island University of Rhode Island Plant Clinic Phone: 1-401-874-2750

Growers may also consider purchasing on site disease testing kits. There are currently three companies that manufacture test kits available for on-site testing. Not every company carries kits for all diseases. Note: Kits need to be refrigerated and expiration dates observed.

ImmunoStrips from Agdia Inc. http:www.agdia.com, Phone 1-800-622-4342

AgroCheck Kits from Hydros Inc www.hydros.cc/ Phone 508-540-2229

Alert Kits from Neogen Company, http://www.neogeneurope.com/

For more information see the fact sheet "Diagnostic Test Kits"

Tina Smith and Paul Lopes, University of Massachusetts Leanne Pundt, University of Connecticut Heather Faubert, University of Rhode Island