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Brown Spots/ Rusty spots, young plant HELP


New Member
Hey guys ive got some brown spots on one of my plants im really not sure what it is. Ive looked in the pest and disease pictorial and cant find anything that matches it.

Ill post some pics My PH is 6.7
using a 150w cfl
ventilation is just a fan but its keeping it cool.
no nutes.


Any help is appreciated really dont want this one to die was looking so healthy before


nordy rascal

New Member
Peace brownbud,
I hope you find this of help, copy and paste it to your documents for future reference, what soil are you using?, it looks like wood bark lol, whatever the prob is im sure it can be rectified with alittle knowledge. :peace2:

Marijuana Grower's Handbook - part 16 of 33

by pH Imbalance


[Indoor/Greenhouse Edition]

Ed Rosenthal

Marijuana requires a total of 14 nutrients which it obtains through its roots. Nitrogen (N), Phosophorous (P), and Potassium (K) are called the macro-nutrients because they are used in large quantities by the plant. The percentages of N, P, and K are always listed in the same order on fertilizer packages.

Calcium (Ca), sulfur (S), and magnesium (Mg) are also required by the plants in fairly large quantities. These are often called the secondary nutrients.

Smaller amounts of iron (Fe), zinc (Zn), manganese (Mn), boron (B), cobalt (Co), copper (Cu), molybdenum (Mo) and chlorine (Cl) are also needed. These are called micro-nutrients.

[pH:And you thought chemistry wasn't good for anything!]

Marijuana requires more N before flowering than later in its cycle. When it begins to flowe, marijuana's use of P increases. Potassium requirements increase after plants are fertilized as a result of seed production.

Plants which are being grown in soil mixes or mixes with nutrients added such as compost, manure or time-releasing fertilizers may need no additional fertilizing or only supplemental amounts of the plants begin to show deficiencies.

The two easiest and most reliable ways to meet the plant's needs are to use a prepared hydroponic fertilizer or an organic water-soluble fertilizer. Hydroponic fertilizers are blended as complete balanced formulas. Most non-hydroponic fertilizers usually contain only the macronutrients (N, P, and K). Organic fertilizers such as fish emulsion and other blends contain trace elements which are found in the organic matter from which they are derived.

Most indoor plant fertilizers are water-soluble. A few of them are time-release formulas which are mixed into the medium as it is being prepared. Plants grown in soil mixes can usually get along using regular fertilizers but plants grown in prepared soilless mixes definitely require micronutrients.

As the seeds germinate they are given a nutrient solution high in N such as a 20-10-10 or 17-10-12. These are just two possible formulas; any with a high proportion of N will do.

Formulas which are not especially high in N can be used and supplemented with a high N ferilizer such as fish emulsion (which may create an odor) or the Sudbury X component fertilizer which is listed 44-0-0. Urine is also very high in N and is easily absorbed by the plants. It should be diluted to one cup urine per gallon of water.

The plants should be kept on a high N fertilizer regimen until they are put into the flowering regimen.

During the flowering cycle, the plants do best with a formula lower in N and higher in P, which promotes bloom. A fertilizer such as 5-20-10 or 10-19-12 will do. (Once again, these are typical formulas, similar ones will do).

Growers who make their own nutrient mixes based on parts per million of nutrient generally use the following formulas.

Chart 15-1: Nutrient/Water Solution In Parts Per Million (PPM)


| | N | P | K |


| Germination - 15 to 20 days | 110-150 | 70-100 | 50-75 |


| Fast Growth | 200-250 | 60-80 | 150-200 |


| Pre-Flowering | 70-100 | 100-150 | 75-100 |

| 2 weeks before turning light down | | | |


| Flowering | 0-50 | 100-150 | 50-75 |


| Seeding - fertilized flowers | 100-200 | 70-100 | 100-150 |


Plants can be grown using a nutrient solution containing no N for the last 10 days. Many of the larger leaves yellow and wither as the N migrates from the old to the new growth. The buds are less green and have less of a minty (chlorophyll) taste.

Many cultivators use several brands and formulas of fertilizer. They either mix them together in solution or switch brands each feeding.

Plant N requirements vary by weather as well as growth cycle. Plants growing under hot conditions are given 10-20% less N or else they tend to elongate and to grow thinner, weaker stalks. Plants in a cool or cold regimen may be given 10-20% more N. More N is given under high light conditions, less is used under low light conditions.

Organic growers can make "teas" from organic nutrients by soaking them in water. Organic nutrients usually contain micronutrients as well as the primary ones. Manures and blood meal are among the most popular organic teas, but other organic sources of nutrients include urine, which may be the best source for N, as well as blood meal and tankage. Organic fertilizers vary in their formulas. The exact formula is usually listed on the label.

Here is a list of common organic fertilizers which can be used to make teas:

Chart 15-2: Organic Fertilizers


| Fertilizer | N | P | K | Remarks |


| Bloodmeal | 15 | 1.3 | .7 | Releases nutrients easily |


| Cow manure | 1.5 | .85 | 1.75 | The classic tea. Well- |

| (dried) | | | | balanced formula. Medium |

| | | | | availability. |


| Dried blood | 13 | 3 | 0 | Nutrients dissolve easier |

| | | | | than bloodmeal |


| Chicken manure | 3.5 | 1.5 | .85 | Excellent nutrients |


| Wood ashes | 0 | 1.5 | 7 | Water-soluble. Very alkaline |

| | | | | except with acid wood such |

| | | | | as walnut |


| Granite dust | 0 | 0 | 5 | Dissolves slowly |


| Rock phosphate | 0 | 35 | 0 | Dissolves gradually |

| (phosphorous) | | | | |


| Urine (human, | .5 | .003 | .003 | N immediately available |

| fresh) | | | | |


Commercial water-soluble fertilizers are available. Fish emulsion fertilizer comes in 5-1-1 and 5-2-2 formulas and has been used by satisfied growers for years.

A grower cannot go wrong changing hydroponic water/nutrient solutions at least once a month. Once every two weeks is even better. The old solution could be measured, reformulated, supplemented and re-used; unless large amounts of fertilizer are used, such as in a large commercial greenhouse, it is not worth the effort. The old solution may have many nutrients left, but it may be unbalanced since the plants have drawn specific chemicals. The water can be used to water houseplants or an outdoor garden, or to enrich a compost pile.

Experienced growers fertilize by eyeing the plants and trying to determine their needs when minor symptoms of deficiencies become apparent. If the nutrient added cures the deficiency, the plant usually responds in apparent ways within one or two days. First the spread of the symptom stops. With some minerals, plant parts that were not too badly damaged begin to repair themselves. Plant parts which were slightly discolored may return to normal. Plant parts which were severely damaged or suffered from necrosis do not recover. The most dramatic changes usually appear in new growth. These parts grow normally. A grower can tell just by plant parts which part grew before deficiencies were corrected. [pH:What's in yer nuggets? Parts. Plant parts. Processed plant parts. HAHAHAHAHAHAHA]

Fertilizers should be applied on the low side of recommended rates. Overdoses quickly (within hours) result in wilting and then death. The symptoms are a sudden wilt with leaves curled under. To save plants suffering from toxic overdoses of nutrients, plain water is run through systems to wash out the medium.

Gardens with drainage can be cared for using a method commercial nurseries employ. The plants are watered each time with a dilute nutrient/water solution, usually 20-25% of full strength. Excess water runs off. While this method uses more water and nutrients than other techniques, it is easy to set up and maintain.

When nutrient deficiencies occur, especially multiple or micronutrient deficiencies, there is a good chance that the minerals are locked up (precipitated) because of pH. [pH:That's not very fair, I wasn't even there!] Rather than just adding more nutrients, the pH must be checked first. If needed, the pH must be changed by adjusting the water.

If the pH is too high, the water is made a lower pH than it would ordinarily be; if too low the water is made a higher pH. To get nutrients to the plant parts immediately, a dilute foliar spray is used. If the plant does not respond to the foliar spray, it is being treated with the wrong nutrient.


Nitrogen (N)

Marijuana uses more N than any other nutrient. It is used in the manufacture of chlorophyll. N migrates from old growth to new, so that a shortage is likely to cause first pale green leaves and then the yellowing and withering of the lowers leaves as the nitrogen travels to new buds. Other deficiency symptoms include smaller leaves, slow growth and a sparse rather than bushy profile.

N-deficient plants respond quickly to fertilization. Within a day or two, pale leaves become greener and the rate and size of new growth increases. Good water-soluble sources of nitrogen include most indoor and hydroponic fertizliers, fish emulsion, and urine, along with teas made from manures, dried blood or bloodmeal. There are many organic additives which release N over a period of time that can be added to the medium at the time of planting. These include manures, blood, cottonseed meal, hair, fur, or tankage.

Phosphorous (P)

P is used by plants in the transfer of light energy to chemical compounds. It is also used in large quantities for root growth and flowering. Marijuana uses P mostly during early growth and flowering.

Fertilizers and nutrient mixes usually supply adequate amounts of P during growth stages so plants usually do not experience a deficiency. Rock phosphate and bone meal are the organic fertilizers usually recommended for P deficiency. However they release the mineral slowly, and are more suited to outdoor gardening than indoors. They can be added to medium to supplement soluble fertilizers.

P-devicient plants have small dark green leaves, with red stems and red veins. The tips of lower leaves sometimes die. Eventually the entire lower leaves yellow and die. Fertilization affects only new growth.

Marijuana uses large quantities of P during flowering. Many fertilizer manufacturers sell mixes high in P specifically for blooming plants.

Potassium (K)

K is used by plants to regulate carbohydrate metabolism, chlorophyll synthesis, and protein synthesis as well as to provide resistance to disease. Adequate amounts of K result in strong, sturdy stems while slightly deficient plants often grow taller, thinner stems. Plants producing seed use large amounts of K. Breeding plants can be given K supplements to assure well-developed seed.

Symptoms of greater deficiencies are more apparent on the sun leaves (the large lower leaves). Necrotic patches are found on the leaf tips and then in patches throughout the leaf. The leaves also look pale green.

Stems and flowers on some plants turn deep red or purple as a result of K deficiencies. However, red stems are a genetic characteristic of some plants so this symptom is not foolproof. Outdoors, a cold spell can precipitate K and make it unavailable to the plants, so that almost overnight the flowers and stems turn purple.

K deficiency can be treated with any high-K fertilizer. Old growth does not absorb the nutrient and will not be affected. However, the new growth will show no signs of deficiency within 2 weeks. For faster results the fetilizer can be used as a foliar spray. K deficiency does not seem to be a crucial problem. Except for the few symptoms, plants do not seem to be affected by it.

Calcium (Ca)

Ca is used during cell splitting, and to build the cell membranes. Marijuana also stores "excess" Ca for reasons unknown. I have never seen a case of Ca deficiency in cannabis. Soils and fertilizers usually contain adequate amounts. It should be added to planting mixes when they are being formulated at the rate of 1 tablespoon per gallon or 1/2 cup per cubic foot of medium.

Sulfur (S)

S is used by the plant to help regulate metabolism, and as a constituent of some vitamins, amino acids and proteins. It is plentiful in soil and hydroponic mixes.

S deficiencies are rare. First, new growth yellows and the entire plant pales.

s deficiencies are easily solved using Epsom salts at the rate of 1 tablespoon per gallon of water.

Magnesium (Mg)

Mg is the central atom in chlorophyll and is also used in production of carbohydrates. (Chlorophyll looks just like hemoglobin in blood, but has a Mg atom. Hemoglobin has an Fe atom). In potted plants, Mg deficiency is fairly common, since many otherwise well-balanced fertilizers do not contain it.

Deficiency symptoms start on the lower leaves which turn yellow, leaving only the veins green. The leaves curl up and die along the tips and edges. Growing shoots are pale green and, as the condition continues, turn almost white.

Mg deficiency is easily treated using Epsom salts (MgSO4) at the rate of 1 tablespoon per gallon of water. For faster results, a foliar spray is used. Once Mg deficiency occurs, Epsom salts should be added to the solution each time it is changed. Dolomitic limestone contains large amounts of Mg.

Iron (Fe)

Fe deficiency is not uncommon. The growing shoots are pale or white, leaving only dark green veins. The symptoms appear similar to Mg deficiencies but Fe deficiencies do not affect the lower leaves. Fe deficiencies are often the result of acid-alkalinity imbalances.

Fe deficiencies sometimes occur together with zinc (Zn) and manganese (Mn) deficiencies so that several symptoms appear simultaneously.

Deficiencies can be corrected by adjusting the pH, adding rusty water to the medium, or using a commercial supplement. Fe supplements are sold alone or in a mix combined with Zn and Mn. To prevent deficiencies, some growers add a few rusting nails to each container. One grower using a reservoir system added a pound of nails to the holding tank. The nails added Fe to the nutrient solution as they rusted. Dilute foliar sprays can be used to treat deficiencies.

Manganese (Mn)

Symptoms of Mn deficiency include yellowing and dying of tissue between veins, first appearing on new growth and then throughout the plant.

Deficiencies are solved using an Fe-Zn-Mn supplement.

Zinc (Zn)

Zn deficiency is noted first as yellowing and necrosis of older leaf margins and tips and then as twisted, curled new growth. Treatment with a Fe-Zn-Mn supplement quickly relieves symptoms. A foliar spray speeds the nutrients to the leaf tissue.

Boron (B)

B deficiency is uncommon and does not usually occur indoors.

Symptoms of B deficiency start at the growing tips, which turn grey or brown and then die. This spreads to the lateral shoots.

A B deficiency (pH:A, B, deficient C!) is treated by using 1/2 teaspoon boric acid, available in pharmacies, added to a gallon of water. One treatment is usually sufficient.

Molybdenum (Mo)

Mo is used by plants in the conversion of N to forms that the plant can use. It is also a consituent of some enzymes. Deficiency is unusual indoors.

Symptoms start with paleness, then yellowing of middle leaves which progress to the new shoots and growing tips, which grow twisted. The early symptoms almost mimic N deficiency. Treatment with N may temporarily relieve the symptoms but they return within a few weeks.

Mo is included in hydroponic fertilizers and in some trace element mixes. It can be used as a foliar spray.

Copper (Cu)

Cu is used by plants in the transfer of electrical charges which are manipulated by the plant to absorb nutrients and water. It is also used in the regulation of water content and is a constituent of some enzymes.

Cu deficiencies are rare and mimic symptoms of overfertilization. The leaves are limp and turn under at the edges. Tips and edges of the leaves may die and whole plant looks wilted.

A fungicide, copper sulfate, (CuSO$) can be used as a foliar spray to relieve the deficiency.


Various additives are often suggested to boost the nutrient value of the water/nutrient solution. Here are some of them:

WETTING AGENTS. Water holds together through surface tension, preventing it from dispersing easily over dry surfaces. Wetting agents decrease the surface tension and allow the water to easily penetrate evenly throughout the medium preventing dry spots. Wetting agents are helpful when they are used with fresh medium and as an occasional additive. Wetting agents should not be used on a regular basis. They may interfere with plants' ability to grow root hairs, which are ordinarily found on the roots. They are available at most plant nurseries.

SEAWEED. Washed, ground seaweed contains many trace elements and minerals used by plants. It may also contain some hormones or organic nutrients not yet identified.

KELP. Kelp seems to be similar to seaweed in nutrient value. Proponents claim that it has other, as yet undefined organic chemicals that boost plant growth.

SEA WATER. Salt water contains many trace elements and organic compounds. Some hydroponists claim that adding 5-10% sea water to the nutrient solution prevents trace element problems. It may be risky.


Suspected Element


| Symptoms | N | P | K | Mg | Fe | Cu | Zn | B | Mo | Mn| Over |

| | | | | | | | | | | |Fertil|


| Yellowing of: | | | | | | | | | | | |

| | | | | | | | | | | | |

| Younger leaves | | | | | X | | | | | X | |


| Middle leaves | | | | | | | | | X | | |


| Older leaves | X | | X | X | | | X | | | | |


| Between veins | | | | X | | | | | | X | |


| Old leaves drop | X | | | | | | | | | | |


| Leaf Curl Over | | | | X | | | | | | | |


| Leaf Curl Under | | | X | | | X | | | | | X |


| Leaf tips burn | | | | | | | | | | | |

| | | | | | | | | | | | |

| Younger leaves | | | | | | | | X | | | |


| Older leaves | X | | | | | | X | | | | |


| Young leaves wrinkle | | | | | | | | | | | |

| and curl | | | X | | | | X | X | X | | |


| Necrosis | | | X | X | X | | X | | | X | |


| Leaf growth stunted | X | X | | | | | | | | | |


| Dark green/purplish | | | | | | | | | | | |

| leaves and stems | | X | | | | | | | | | |


| Pale green leaf color| X | | | | | | | | X | | |


| Mottling | | | | | | | X | | | | |


| Spindly | X | | | | | | | | | | |


| Soft stems | X | | X | | | | | | | | |


| Hard/brittle stems | | X | X | | | | | | | | |


| Growing tips die | | | X | | | | | X | | | |


| Stunted root growth | | X | | | | | | | | | |


| Wilting | | | | | | X | | | | | |


nordy rascal

New Member
Have you checked for mites and bugs?, your pH levels seem fine and you havnt used nutes yet, so if you havnt over watered it and it hasnt got bugs "some of which can be minute"... (mine...ute) meaning very small lol >>> spellings crap <<<, but im from northern ireland so ive a license to be stoooopid :thumb:, just make sure the lights arnt too close and good luck brownbud. :peace2:

nordy rascal

New Member
Peace, from looking at the new growth it seems that the prob has moved on, one golden rule that ive learnt as a new grower is "less is good", rem cannabis are part of the bigger picture and God will look after your girls, offer a grow medium, water wisely and read 420 tutorials... and "alls good in the hood" :peace2:
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