Nutrient Disorder Problem Solver by Jackerspackle

To utilize the Problem-Solver, begin with step #1 outlined below. Once you've identified a potential issue, refer to the Nutrients section to gain a deeper understanding. Ensure to diagnose with precision prior to implementing significant alterations.

1) Is the issue localized at the bottom or middle of the plant? Proceed to #2. If it's at the top or the growing tips, move ahead to #10. Should the entire plant appear uniformly affected, jump to #6.

2) Leaves exhibit a consistent yellow or light green hue; they wither and fall off; growth is stunted; leaf edges are not noticeably curled. Likely a Nitrogen (N) deficiency. If this doesn't match, continue to #3.

3) The leaf edges are curled upwards, possibly with twisted tips. Leaves are turning yellow, potentially browning, while veins remain more green. This suggests a Magnesium (Mg) deficiency. If not, head to #4.

4) Leaves are displaying browning or yellowing, with yellow, brown, or dead patches, particularly at the margins which may also be curled. The plant may appear excessively tall. This could be a Potassium (K) deficiency. If not, read on.

5) Leaves are unusually dark green or have a red/purple tint. Stems and petioles might show similar discoloration. Leaves could yellow or curl under, drop prematurely, while growth is inhibited and leaves are undersized. These are signs of a Phosphorus (P) deficiency. If not applicable, go to #6.

6) Leaf tips are yellow, brown, or dead while the rest of the plant remains vibrant and green. Stems might feel soft. This could be a result of over-fertilization (especially with Nitrogen), overwatering, damaged roots, or lack of soil aeration (improve with more sand or perlite). Sometimes it may indicate a deficiency in N, P, or K. If this isn't the case, proceed to #7.

7) Leaves curl under like a ram's horn and display dark green, gray, brown, or gold coloration. This is typically due to excessive Nitrogen. If not, continue to #8.

8) The plant appears wilted despite moist soil. This could indicate over-fertilization, waterlogged soil, root damage, disease, or in rare cases, a copper deficiency. If not, advance to #9.

9) Plants fail to flower after over two weeks of 12-hour darkness periods. Causes could be insufficient darkness at night, too much nitrogen, or excessive pruning or cloning. If not, go on to #10.

10) Leaves turn yellow or white while veins stay mostly green. This is indicative of an Iron (Fe) deficiency. If not, proceed to #11.

11) Starting from the base, leaves turn light green or yellow, but the margins stay green. Between the veins, necrotic spots may appear. Leaves are not contorted. This points to a Manganese (Mn) deficiency. If not, go to #12.

12) Leaves are contorted, yet the symptoms are largely similar to those described in #11. This denotes a Zinc (Zn) deficiency. If not, continue to #13.

13) Leaves begin to twist, then brown or die. This could be due to overly close lighting to the plant, or rarely, a Calcium (Ca) or Boron (B) deficiency. If not, the issue may be a weak plant.


Nitrogen (N) is crucial for plant growth during the vegetative stage, but over-application is common. If you've added too much nitrogen, flush the soil with water. Plants absorb soluble nitrogen forms, like nitrate, quickly, but insoluble forms such as urea require soil microbes to break them down first. High levels of ammonium nitrogen can disrupt the uptake of other nutrients and delay the onset of flowering. Nearing the end of the flowering phase, it's beneficial to let plants experience a slight nitrogen deficiency to enhance flavor.

Magnesium (Mg) is often deficient because it's heavily used by plants and not present in sufficient quantities in many fertilizers. Correct a magnesium deficiency with a teaspoon per gallon of Epsom salts, dissolving it in hot water first, or apply as a foliar spray at a teaspoon per quart. When preparing soil, add 2 teaspoons of dolomite lime per gallon to provide magnesium. Excess calcium (Ca), chlorine (Cl), or ammonium nitrogen can inhibit magnesium absorption. Avoid adding too much magnesium to prevent locking out other nutrients.

Potassium (K) deficiencies can be caused by excessive sodium (Na), which competes with potassium for uptake. High sodium sources include sodium bicarbonate used for pH adjustments, excessive manure, and using water-softening filters. To address sodium issues, flush the soil with water. Excess calcium or ammonium nitrogen and cold conditions can also lock out potassium.

Phosphorus (P) may be slightly deficient during flowering, but severe deficiencies are problematic. Red petioles and stems can be normal for some strains or indicate combined deficiencies of N, K, and Mg. Overabundance of phosphorus can lead to iron deficiencies.

Iron (Fe) becomes unavailable when the pH is too high. To remedy an iron deficiency, adjust the pH to around 6.5, or 5.7 for rockwool, and ensure phosphorus levels aren't too high, which can interfere with iron uptake. Use chelated iron for better plant availability, which may be listed as "iron EDTA" on fertilizer labels. Adding too much iron without sufficient phosphorus can cause a phosphorus deficiency.

Manganese (Mn) is not absorbed well when the pH is high or when iron levels are excessive. Use chelated manganese to correct deficiencies.

Zinc (Zn) is also affected by high pH. Zinc, iron, and manganese deficiencies often occur together, usually due to high pH levels. Avoid over-applying micro-nutrients and adjust the pH if necessary to make them available. Employ foliar feeding in severe cases, using chelated zinc.

Monitoring your water is crucial. Hard water is indicated by crusty faucets and shower heads, often with a TDS level over 200ppm. Contact your water company for a detailed water analysis. To reduce high TDS levels, consider reverse-osmosis units, distillers, or de-ionizers. A digital TDS or EC meter can help you keep track of nutrient concentrations.

When feeding plants, use higher nitrogen and lower phosphorus ratios during vegetative growth, and the reverse during flowering. For vegetative growth, aim for an N:P:K ratio of around 10:7:8, and for flowering, a ratio of 4:8:8. Always check the pH after mixing nutrients, keep reservoirs circulating, and change the nutrient solution every two weeks. TDS levels vary based on the plant's growth stage, with general guidelines being: seedlings = 50-150 ppm; unrooted clones = 100-350 ppm; small plants = 400-800 ppm; large plants = 900-1800 ppm; and taper off to plain water in the last week of flowering. These guidelines are not absolute, and factors like organic nutrients might not show accurately on TDS meters.

The ideal pH range after nutrient addition is between 5.9 and 6.5, or 5.5 to 6.1 for rockwool. High pH can lock out micro-nutrients like Fe, Zn, Mn, and Cu, while low pH can reduce the availability of major nutrients like N, P, K, and Mg. To accurately measure pH, invest in a digital pH meter.

Cold temperatures can inhibit phosphorus uptake, and some strains, particularly equatorial sativas, don't tolerate cold well. Keep root zones warm to help plants withstand cooler temperatures.

Heat can cause the plant tops to curl and appear burnt if the lights are too close. Ensure your hand doesn't feel hot above the plants, adjust light height, and use fans if necessary. Maintain room temperatures below 85F or 90F with additional CO2.

Humidity levels between 40-80% are generally appropriate, but low humidity can lead to thin, shriveled leaves.

Mold and fungus can be identified by dark, patchy areas on leaves and buds. Reduce humidity and increase airflow to combat mold. Remove any dead plant material to maintain cleanliness.

Insects like spider mites leave white spots on leaf surfaces.

Foliar sprays can cause a magnifying effect under bright lights, leading to leaf discoloration that may be mistaken for nutrient issues. Chemical reactions from sprays can also occur.

Insufficient lighting can cause plants to stretch. Avoid regular incandescent bulbs or halogens; instead, use fluorescent or HID lighting, or ideally, natural sunlight.

For clones, yellowing leaves may result from too much light or the stem not contacting the rooting medium. Avoid using CO2 until they root, and use plain tap water instead of fertilizers to avoid overfeeding.