Nutrient Basics - Manganese

Manganese plays a structural role in the chloroplast membrane system, and also is important in numerous enzymes allowing them to work properly.

A manganese deficiency is difficult to diagnose since it resembles an iron deficiency. Yellowing (chlorosis) is most severe at the top of the plant. Yellowing of the leaves appears first near leaf margins and develops in a V-shaped pattern. Leaves then develop tan or gray spots that can easily be mistaken for air pollution damage. These spots are the major difference between manganese and iron deficiency.

Good growers know manganese gets locked out when the pH is too high, and when there's too much iron. Use chelated Mn if you have a deficiency.

Causes of manganese deficiencies are soils with a high pH (Alkaline), soils high in humus or peaty soils.

Manganese Toxicity appears as chlorosis, or blotchy leaf tissue due to insufficient chlorophyll synthesis. Growth rate will slow and vigor will decline.

Good Growing,
Dr. E.R. Myers


Nutrient Basics - Iron

Iron is an important component of some plant enzymes so while it is needed in small amounts, if it is deficinet you will not gave the best growth you can bet.

With an iron (Fe) deficiency like all movable nutrient deficiencies you will notice the change at the top of the plant as it works its way down. With an Iron deficiency look for the leaves to turn yellow but retain green veins. Shoots may die back and fruit may be discolored.

Causes of iron deficines are alkaline soil, (i.e. basic sols that are way above 7.0), applying too much phosphorus, over watering *The number one problem people have when E-mailing me*, excessive soluble salts, inadequate drainage. The good news, this is easily corrected by adding an iron supplement with the next watering.

Good growers know iron is unavailable to plants when the pH of the water or soil is too high. If iron appears to be deficient, lower the pH to about 6.5 (for rockwool, about 5.7), and check that you're not adding too much phosphorus, which as I said above can lock up iron. Use iron that's chelated for maximum availability. Read your fertilizer's ingredients - chelated iron might read something like "iron EDTA". Keep in mind too much iron without adding enough P can cause a P-deficiency.

You should also know that when adding iron to the solution, it is often necessary to not use fertilizer for that watering. Iron has a tendency of reacting with many of the components of fertilizer solutions, and will cause nutrient lockup to occur. Read the labels of both the iron supplement and the fertilizer you are using before you attempt to combine the two.

Iron Toxicity is rare but could cause brown spots on leaf surface.

Good Growing,
Dr. E.R. Myers


Nutrient Basics - Sulfur

Sulfur or sulfate is involved in protein synthesis. It is important in plant metabolism and involved with synthesis and breakdown of fatty acids.

A Sulfur deficiency looks like a nitrogen deficiency accept it shows up in the young leaves first. The young leaves will show yellowing of the entire leaf including veins but usually do not dry out. Also, you may notice the stems are weak. You may notice the leaf tips may yellow and curl downward. Some plants may show purple at the tips of the branches. Purple color is normal in some plant varieties but not usually just at the growing tip.

Causes of Sulfur deficiency are very wet or sandy soils or when soils contain an excess of nitrogen

As with any nutrient too much is just as bad as too little sulfur toxicity will show up with leaf size being reduced and overall growth will be stunted. You will also notice leaves yellowing or scorched at the edges. Excess sulfur may cause early senescence (when plants begin to die back for the winter)

Good Growing,
Dr. E.R. Myers


Nutrient Basics - Calcium

Calcium plays an important role at the cellular and molecular level in plants. This means it helps plant cells to function properly.

Symptoms of Calcium Deficiencies - first appear in new growth. Young leaves are affected first and become small and/or chlorotic (yellow or white to yellow) with irregular margins, spotting or necrotic areas. Chlorosis begins first at leaf edges then moves in. You may also notice young leaves become crinkled. Stem shoots stop growing and thicken and terminal buds become distorted. For indoor growers you should first rule out heat stress as a cause of the symptoms which has the same symptoms. You can tell if the problems are do to heat stress because this damage occurs only at the tops of the plants closest to the lamps. If you have a calcium deficiency the tips of all branches (not just the branches at the top of the plant by the light) will show symptoms. There's only one cure for heat stress problems...get the heat away from the plants, either by moving the lamps or moving the plants.

Causes of calcium deficiencies are acid soils/grow mediums, sandy soils. Soils that contain an excess of magnesium or potassium can cause calcium problems too. Temporary calcium problems may be due to drought or excess moisture but this should not be a problem indoors.

Good growers will look for calcium as a micronutrient in fertilizers; it is not in all fertilizers. Organic sources of calcium are eggshells. I put egg shells in my compost to ensure the compost has calcium in it. And. if you like seafood or live by the ocean you might have access to oyster shells. You can grind or break these up and soak them in water you plan to use to water your plants with.  You could even add some shell pieces to the hydroponic resevoir or soil.

Good Growing,
Dr. E.R. Myers


E-mail LED's and Clones/Cuttings

Hey I just placed a full order form you guys this morning and can’t wait till it gets here! I was wondering, can I use the 120w LED Starship during the cloning phase or should I use something else?.


I have posted on the blog about using LED’s for seedlings and flowering.   I have had good success with LED’s for, cloning, vegetative and flowering. One word of caution however, I have had quite a few people write about how the LED”s have burnt their plants. These people used the LED's incorrectly and had them a few inches above their plants.  See my post on light height. This ‘burnt plant’ problem is not due to heat but from light intensity actually. The LED’s from HTGSupply.com are so intense they can cause the plant pigments to become overwhelmed with light. This will stop photosynthesis and can destroy plant tissue. I would not recommend an LED be closer than one foot above plants and maybe even two feet depending on the plants you are growing. With clones, I would actually recommend keeping the LED three feet above the plants. I say this because with clones, you want a lower light source since they lack roots and an intense light will cause the cuts to use up water in their cells to do photosynthesis. With cuttings you want to have a warm, humid environment and a low light source to maximize success.

Good Growing,
Dr .E.R. Myers