Nutrient Basics - Cobalt

Cobalt is needed by all animals in trace amounts.Cobalt is a component of vitamin B12 which is essential to most animals and possibly plants
    Studies indicate cobalt is essential to many beneficial bacteria that are involved in nitrogen fixation both in legumes and non-legumes. From what I read, the cobalt is actually being used by the beneficial bacteria and the use in plants is still unknown. I would recommend having cobalt in a fertilizer if you are going to use beneficial bacteria of any type.  There is still a lot of unknowns about cobalt.
 Cobalt is needed in VERY small amounts.  It is toxic to people in large amounts, a few grams will kill a 200 pound person so do NOT search out large quantities.  You should not touch cobalt with your bare hands.  It was used to settle beer foam in Canada a few years ago and it lead to heart problems.

Good Growing,
Dr. E.R. Myers


Nutrient Basics - Molybdenum


As I wrap up my nutrient basics series of articles I want to suggest to the good growers that molybdenum and the next post on cobalt are two nutrients that may benefit the beneficial organsims as much or more than the plant it self. Molybdenum is proven to benefit symbiotic nitrogen fixation and it is used by plants for protein synthesis.

Molybdenum deficiencies show up as leaves of young plants are chloritic, leaf margins yellow and curl. Older leaves become abnormally large, while young leaves remain very small You may also notice interveinal chlorosis which occurs first on older leaves, then progresses to the entire plant. Molybdenum deficiencies frequently resemble nitrogen deficiencies, with older leaves chlorotic with rolled/curled margins and stunted growth. If you are adding a high nitrogen fertilizer during vegetative growth you should look for twisted younger leaves which eventually die which means it is molybdenum and not nitrogen..

Casues are usually due to pH, often with acidic soils (soils with a pH of 5.2 and below). An excess of sulfur or copper can also cause a molybdenum deficiency.

Molybdenum toxicity will cause a discoloration of leaves depending on plant species. This condition is rare but could occur. You will notice it right away after adding a fertilizer that is high in molybdenum. Since it is used by the plant in very small quantities, I would not recommend adding it. I say this not just to avoid harming your plant, there may be health effects from consumption of high amounts of molybdenum so if you are not 100% sure you have a deficiency, don’t worry about it.
Good Growing,
Dr. E.R. Myers


E-mail- Brown leaf tips

I have noticed the tips of my leaves have brown tips.  What does this mean and if it is a problem how can I fix it?

Thanks for your question.
Browning of leaf tips or leaf margins (leaf edges are called margins) can be caused by a few different things. The first thing I would guess being an indoor gardener is a lack of humidity. If you don’t have one, you should think about getting a thermometer with a min/max setting for temperature and humidity. I have one that takes the humidity reading on a remote wire. I like this because you can put the sensor by your plant tops near the light to be sure the temperature and humidity are in their optimal range by the plant tops, and then you can put the base by your plant pots/floor to see what the humidity and temperature are down there. If you use an HPS or MH these bulbs generate a lot of heat (which can also cause leaf tips to burn) and also reduce humidity. This low humidity can be good as low humidity is bad for spider mites (LINK) and fungal disease, but also not the best situation for your plants. If you do have low humidity (30% or less) I think this may be something (brown leaf tips) you may want to live with. You can mist your plants, have the pots sit in trays with stones and standing water and water you plants a bit more often, but all these can have negative side effects. If the brown tips do not get worst, or you do not see other leaf discoloration the best thing might be to do nothing.

Brown leaf tips and brown along the margins can also be a sign of fertilizer burn and/or poor water quality. If you are using more than the recommended amount of fertilizer the brown tips are a sign you should not add more or reduce the amount of fertilizer. If your water has high amounts of chlorine or chloramines you could consider a water filter. Lastly, if you are using an insecticidal soap this may cause brown leaf tips.
Please feel free to send me any more questions if you have them.
Good Growing,
Dr. E.R. Myers


Nutrient Basics - Copper

Copper is part of many plant enzymes so it is essential for plants to have trace amounts of this nutrient.

Copper deficiencies appear in young leaves in a unique way, leaf centers yellow while veins and leaf margins remain green for a while. Shoots tips die, which is seen as leaves fail to develop. If they do grow, young leaves often become dark green and twisted. They may die back or just exhibit necrotic spots. Overall growth and yield will be deficient as well.

Causes of copper deficiencies are usually due to pH, plants grown in peat soils or given too much lime. Excess phosphorus, zinc or nitrogen can also cause a copper deficiency

As with any nutrient, copper toxicity is possible. Good Growers know copper is required only in very small amounts and readily becomes toxic in solution. Excess values will induce iron deficiency. Root growth will be stunted showing reduced branching, abnormal darkening and thickening of roots.

Good Growing,
Dr. E.R. Myers