Nutrients (plant food, fertilizer) feed your plants. MACRONUTRIENTS andMICRO NUTRIENTS make up the diet of your plants. Micronutrients are tiny amounts of elements that are provided in your nutrients. Their use is well understood, but all you have to do is supply them.
Macronutrients are the biggies – the NPK and such. Each of these nutrients has a particular purpose and a particular effect. Too much or too little of these and you will have problems.
Even the best nutrients can run up against a weird strain of tomato or have an odd reaction to certain types of basil. Knowing your varieties’ needs and your nutrients’ capabilities will help make your growing experience successful.
Nutrients are either mobile or immobile. Mobile means that the plant can transfer this nutrient to other parts of the plant as needed. The oldest nutrients in this group are found in new growth, since the lowest part of the plant will absorb the mobile nutrient first, releasing it to other parts of the plants as necessary. Nutrient deficiencies in mobile nutrients appear on the oldest leaves first. Immobile nutrients remain deposited in their original place in older leaves. New growth will exhibit deficiencies with these nutrients first.

Even the best nutrients can run up against a weird strain of tomato or have an odd reaction to certain types of basil. Knowing your varieties’ needs and your nutrients’ capabilities will help make your growing experience successful.

NITROGEN (N) mobile

This causes your plant to grow green and healthy. It is the most abundant of the macros. It also moves around in your plant.

When there is too little N, your plant will move the nitrogen from the older leaves to the newer, leaving the older leaves chlorotic, which is a yellowing of the leaves. Low N causes stunting and abnormally thin shoots. It also slows flower production. Treat by increasing the N of your solution.

Too much N causes very dark green leaves, which are less hardy and prone to insect and disease attack, and root pathogens such as pythium. Treat by flushing your plants with 3X the volume of clean water to your growing medium. Feed with a 0% N nutrient for a week to allow the plant to use up the excess N.


This is a vital part of the energy molecules found throughout your plants. It is necessary in root and bloom development.

Too little P causes slow growth, leaves pick up a blue or purple tint, thin stems occur, and there are longer distances between the branches. Purplish-black blotches will develop on leaves. Older leaf tip curl down and turn dark. Leaf curl and drop is a sign of severe distress. Too low a pH or lack of oxygen in the soil will aggravate this condition.
Add a high P additive to your base nutrient schedule. Check for pH, and aerate soil if possible.
Too much P interferes with iron, magnesium, and zinc absorption. Flushing and foliar feeding with Spray N Grow can help correct these problems.

POTASSIUM (K) mobile

K ions are vital in the system that controls movement of water in and out of leaves. It is vital in aiding the plant’s ability to take up water through the roots. It also is necessary in the energy production and conversion of carbohydrates into sugars.
Like Nitrogen, this is mobile and deficiencies show up in older leaves first. Plants start out with dark green foliage, but lose their luster. Branching may increase, but it is weak and scrawny. The leaves turn gray at the margins and progress to a rusty color and curl up and dry. Flowering is retarded and greatly diminished. Plants react badly to water stress and wilt easily. Treat with a potash or potassium supplement, but be aware of the pH when using these type of products.
Too much K is not directly toxic to a plant, but can cause magnesium and calcium deficiencies.

CALCIUM (Ca) immobile

Most Ca is found in cell walls, adding structure to the plant and flexibility to cell membranes.
New leaves are the first to show calcium deficiency. Weak stems, very dark green foliage, and extremely slow growth are the first symptoms. Young leaves are malformed, with ragged margins, and eventually turn brown. Roots will turn brown or transparent, and develop a swollen lumpy appearance. Growth is stunted. Blossom end rot on fruit occurs. Treat with a balanced Ca/Mg supplement, such as CalMag.
High humidity will also interfere with Ca absorption.
Too much Ca results in an imbalance with magnesium and potassium. Flush and apply a balanced nutrient.

MAGNESIUM (Mn) mobile

Found in every chlorophyll molecule, Magnesium is vital in the plant’s ability to use light.
Too little Mg causes the bleaching of color between the veins of the leaves. A red or orange tint may appear. At this level, fatality usually occurs. Treat with Epsom salts or a balanced Ca/Mg supplement.
Too much interferes with Calcium use. Mg and Ca should ideally be present in the same amounts.

SULFUR (S) immobile

Sulfur is found in plant hormones which directly affect odor and taste, as well as provide a chemical defense against mold and disease attack.
Too little sulfur causes young leaves to turn lime green to yellowish. Veins will remain green, but the petioles and leaf stems will turn purple. Leaf tips burn, darken, and hook downward. Acute deficiency causes elongated stems the become woody at the base.
Sulfur toxicity is very rare.
The following are micronutrients that might show deficiencies or toxicity:

ZINC (Zn) mobile

This is the most common deficency of the micronutrients, and usually shows up in dry atmospheres and a higher pH.
Zinc is a component in enzyme production, forming chlorophyll, and is crucial for stem growth. Zinc plays a vital role in sugar production.
Zinc deficiency shows up first in new growth. Leaves become yellowed between the veins, and these leaves and growing tips develop small, thin blades that contort and wrinkle.
Burned spots on the leaves spread, and may look like a lack of manganese or iron, but new leaves contort and dry out. Flowers are deformed, turn crispy dry, and hard. All new growth is stunted.
Zinc can also be extremely toxic in excess. It will cause iron to be locked out, or, in large amounts, will kill the plant quickly.
Spray N Grow is a quick foliar fix for this and other micro deficiencies. At the root level, check your nutrients and switch to a nutrient containing a higher percentage of zinc.

MANGANESE (Mn) immobile

This is a component of photosynthesis, enzyme activation, and nitrogen and zinc utilization.
Young leaves show symptoms first. They become yellow between the veins but the veins remain green. Dead spots develop on leaves which become pale and fall off. Plant growth is stunted. Growth slows. Lower the pH, flush the soil, and add a complete micronutrient.
Toxicity is caused by low humidity as well as oversupplying this micro. Young growth develops orange to rusty blotches, growth is slowed, and overall vigor is lost. A low pH can cause toxic uptake. Flush and raise the pH and the humidity.

IRON (Fe) immobile.

Iron is vital to enzyme systems, transportation of gathered energy during photosynthesis, respiration, and the transfer of energy from sugars.Deficiences are common when the pH is above 6.5. Iron deficiencies may appear during rapid growth or stress and then disappear by themselves. The first symptoms appear on smaller leaves with yellowing between the veins. This starts at the leaf petiole rather than the tip.
Treat by lowering the pH, improving drainage in soil, increasing root-zone temperature, and applying chelated iron to the root zone. Keep from exposing your nutrients to light, because light degrades iron.
Toxicity is rare.

Boron (B) immobile

It is rare for Boron to cause any issues. Boron helps with calcium uptake, cell division, and pollen production.

CHLORINE (Cl) immobile

Even though we do our best to remove chlorine from our water, a small amount remains that is useful to the plant for photosynthesis and cell division. Toxicity shows young leaves developing burned leaf tips and margins. Yellowish-bronze leaves are smaller and slower to develop. Treat by flushing with distilled water.

SILICON (Si) immobile

Silicon keeps iron and manganese levels consistent, but its greatest benefit is by thickening the cell walls, providing rigid structure that will assist in holding heavy fruit and flowers without breaking. Thicker leaves function better, with the stomata operating well. Pests find the denser leaf surface more difficult to penetrate, and diseases such as mildew have a harder time getting established. Rhino Skin is one of the best sources of immediate silicon. Using Rocks as a top dressing for soil or as a growing medium for hydro adds silicon as well.


There are dozens of other micronutrients that are adequately supplied with a complete base nutrient system, and should not be of concern.


Selecting a nutrient program can be overwhelming. Every line has so many bottles. The thing is to recognize the different levels of the parts of a good program.
Each nutrient line has its own recipe. Follow the directions. When beginning, select a line and stick with it, unless you have solid advice to mix lines up. Ease of use, reputation, and cost all figure into this decision. Every line works well. Premium lines, such as Advanced, or basic lines such Botanicare, all cover your needs. It then becomes a matter of quality, commitment, and cost to make your decision. Ask around, and check out the home websites of different lines.
Base Nutrients are the foundation of any nutrient program. One part nutrients, such as CNS17, have a single bottle each for grow and bloom. Three part nutrients have grow, micro, and bloom bottles. Some nutrients separate the grow and the bloom components into two separate bottles. The buffering agent needed is decreased with the more bottles because the manufacturer is able to separate the conflicting nutrients. Never mix the components together and then add to the water! Always add each part separately. Mix well before adding the next part.
Base nutrients are sufficient for a successful garden. Nothing more nutritionally is needed.
Supplements are helpful to tweaking maximum use of your nutrients. They include the CaMg supplements, silica such as Rhino Skin, B vitamins, Superthrive, beneficial microbes, root stimulators, enzymes such as Hygrozyme and Sensizym, fulvic and humic acids…anything that ASSISTS the plant’s nutrient health and activity. Adding carbohydrates is relatively new. Carbs become sugars, which in turn are pushed into the fruit, since the plant receives an excess amount. The result is bigger, sweeter fruit, with great aroma and taste. Nearly all carb supplements are flavored, and these flavonoids will transfer to the fruit. They will not make a strawberry taste like a banana, however. What they do is provide an enhancing layer of taste to the already tasty fruit.
Additives are when the fun begins. These are the OMG of nutrients. Big Bud, Bud XL, the Foxfarm trio of powders, and a ton of other ingredients that force your plants into overdrive, rushing to produce the biggest flowers and fruits, and the most flowers and fruit. When using these powerful and effective products, only add the specified amount. Additives push the plant to its maximum, and death can come quickly on an overdose. The rewards are high, but the risk increases.

Remedies are a group that are designed to fix a problem. Spray N Grow foliar spray is great for micro deficiencies, especially zinc and iron. Revive is a tonic for serious stress from drought, bugs, disease, or other near-fatal events. Reverse is a product to treat a hermaphrodite. All of these and others are remedies, though, and with diligence and care can often pull a plant through. They cannot save an abused plant suffering with a neglectful gardener.