- Cultivation specialist Floriculture
- Technical Sales Specialist - Canada
- Crop Supervisor - Australia
- Senior Business development- / Sales Manager - The Netherlands
- Global VP of Sales & Marketing
- Product Manager - Europe
- Product Manager, Horticulture - De Lier, the Netherlands
- Chief Executive Officer - Tropical North Queensland (Tully) Australia
- Head Grower in USA
- Commercial Manager | Cut Flowers - Kenya
Top 5 -yesterday
Top 5 -last week
- "A rose every lady deserves"
- Valentine's Day 2020: Ups and downs in international rose trade
- Netherlands: Higher rose prices as Kenyan supply lags behind
- Dümmen Orange and Perfect Plants sign agreement for collaboration
- The Friday effect and oversupply: the challenges for Colombia’s flower sector in 2020
Top 5 -last month
Role of iron in plant culture
Function of iron
Iron is a constituent of several enzymes and some pigments, and assists in nitrate and sulfate reduction and energy production within the plant. Although iron is not used in the synthesis of chlorophyll (the green pigment in leaves), it is essential for its formation. This explains why plants deficient in iron show chlorosis in the new leaves.
Iron deficiency is expressed as an interveinal chlorosis of the new leaves (leaves are yellow with green veins). To determine the cause of the deficiency, first examine the roots. Plant roots that are diseased or stressed from overwatering do not take up nutrients efficiently, causing chlorosis. It is important to allow the growing medium to dry out between waterings to reduce plant stress, and to apply an appropriate fungicide drench if roots are diseased.
If the roots are healthy, send a sample of the growing medium and plant tissue from several plants to a lab for verification. The pH of the growing medium directly affects the uptake of iron by plants. If the pH of the growing medium exceeds 6.5, iron is converted to a form that is unavailable to the plant, causing deficiency. The pH of the growing medium can be reduced by acidifying the irrigation water and/or using a fertilizer with a higher potential acidity. Since this may take up to a few weeks to correct the problem, chelated iron can be used to quickly green up the plants. The most effective chelating agent is iron-EDDHA. However, iron-DTPA is almost as good.
If testing shows iron is deficient in the growing medium and tissue, but that the growing medium pH is normal, look at the fertilizer application rate. Fertilizing at low nitrogen rates means that iron is also being applied at low rates. Increasing the fertilizer application rate may take care of the problem. However, calibrachoa, diaschia, petunia, scaevola, snapdragon, etc. require additional iron over and above what most fertilizers supply. Therefore, iron chelates may need to be added to your fertilizer program.
Another reason for testing is to check the levels of other micronutrients in the growing medium and tissue. Often, the deficiency symptoms of manganese and other micronutrients look like an iron deficiency. Correcting an iron deficiency will not help if another micronutrient is deficient.
Iron toxicity occurs due to a low growing medium pH or from an excessive application of iron. Iron-manganese toxicity, as it is commonly referred to, is more common in zonal geraniums, African marigolds, lisianthus, New Guinea impatiens, pentas, or other crops that prefer the growing medium's pH to be 5.8-6.6. Again, have the growing medium and tissue tested to confirm the problem. If the pH of the growing medium is a problem, but less than 0.5 pH unit below the normal range for the plant, alternate fertilizer applications with a potentially basic fertilizer (15-0-15, 14-0-14, 13-2-13, etc.) and, if applicable, refrain from injecting acid.
If the pH of the growing medium is more than 0.5 unit below the normal range, drench with potassium bicarbonate or liquid limestone. With either product, rinse the foliage with clear water to remove residues and avoid phytotoxicity. Potassium bicarbonate (2 lb/100 gallons of water) adjusts a growing medium's pH quickly, but provides 933 ppm potassium and increases soluble salt levels in the growing medium. Liquid limestone does not increase EC and has a longer staying power, but takes one week to fully adjust pH. Keep in mind that it is abrasive to injectors and requires agitation in stock solutions.
A few water sources provide sufficient iron for most crops, but this is unusual. Iron is typically provided by a fertilizer and most plants prefer a constant iron application rate of 1 ppm. Plants such as calibrachoa, diaschia, petunia, scaevola, snapdragon, etc. prefer higher iron application rates, so it may be best to supplement with an iron chelate as suggested above.
For more information
Premier Tech Horticulture Office
1, avenue Premier
Canada G5R 6C1
T: +1 418 867-8883
Toll free: +1 855 867-5407
Receive the daily newsletter in your email for free | Click here
Other news in this sector:
- 2020-02-19 LED supplemental lighting providing red and blue radiation = purple leaves on some young plants
- 2020-02-18 Responses of ornamental plants to complementation with monochromic or mixed red-blue LEDs
- 2020-02-17 More light ensures higher production of Alstroemeria
- 2020-02-17 Planting Bletilla in the Westland
- 2020-02-14 Tulips grow in winter, thanks to the summer sun
- 2020-02-12 "Stomata monitor offers promising perspectives"
- 2020-02-05 Tips for rooting difficult or slow-to-root cutting
- 2020-02-04 US (CT): New study identifies ornamental nursery plants used by honey bees for pollen
- 2020-02-04 Are you ready to grow in 2020?
- 2020-01-30 Confusion about diffused light clarified
- 2020-01-30 What does good pollination look like?
- 2020-01-30 Ethiopia will irrigate more than a million hectares before September
- 2020-01-29 "Enrich your data-set, realize yield prediction"
- 2020-01-29 Up to 15% cultivation speed increase with 'Grown with WaterWick' concept
- 2020-01-24 Dutch companies build app to share ornamental horticulture knowledge
- 2020-01-23 Chinese engineer reveals how he grew the first ever plant on the moon
- 2020-01-23 Model the climate and the crops: bring your production to the top
- 2020-01-22 Hydroponic farming of wheat, spinach and sword lily
- 2020-01-22 Specifying irrigation needs for container-grown plants
- 2020-01-22 Top 10 tablet tools