Yellow Spots On Weed Leaves

If you see yellow spots on your weed leaves, then it could be a sign of a mineral deficiency. The good news is that yellow leaf spotting can usually be easily fixed. It’s a common problem for growers and has simple solutions, whether the problem is caused by an overall lack of nutrients, or insufficient levels of nutrients in the soil. If you want to keep your plants healthy and strong, then keep reading to learn how to take care of this issue!

Yellow spots on weed leaves are a sign of a mineral deficiency.

When yellow spots appear on the leaves of your cannabis plants, it’s usually a sign of a mineral deficiency. This can be caused by an overall lack of nutrients or insufficient levels of nutrients in the soil.

The first step is to determine whether the problem is caused by an overall lack of nutrients, or insufficient levels of nutrients in the soil. If you suspect an overall lack of nutrients, then you’ll want to check out this article: Overdosing Cannabis (and How to Avoid It)

It could be nitrogen deficiency, potassium deficiency or magnesium deficiency.

If the yellow spots on your weed leaves are small and round, it could be a sign of nitrogen deficiency.

If your weed leaves have large yellow spots with a green ring around them, then it could be a sign of potassium deficiency.

If your weed leaves have both large and small yellow spots on them, then it could be a sign of magnesium deficiency.

All three of these nutrient deficiencies can cause yellow spots on weed leaves because they all result from lack of nutrients in the soil or water supply for plants to absorb enough nutrients that are essential for healthy growth.

The first step is to determine whether the problem is caused by an overall lack of nutrients, or insufficient levels of nutrients in the soil.

The first step is to determine whether the problem is caused by an overall lack of nutrients, or insufficient levels of nutrients in the soil.

Yellow spots on weed leaves are a sign of a mineral deficiency. This could be nitrogen deficiency, potassium deficiency or magnesium deficiency. To figure out which one it is, you’ll need to do some testing on your soil and/or your plant’s leaves and stems.

The process for testing phosphorus should be similar to what I’ve described above: mix together some water with white vinegar until no bubbles form, then add about half as much hydrogen peroxide as there was vinegar (so if it was 1/4 cup [60 ml] each time around then use 1/8 cup [30 ml] hydrogen peroxide). If there are still bubbles forming when you pour off this solution then you’ll know that either your sample wasn’t mixed properly or else too much iron (which would produce a reddish color) was present in your sample at high concentrations so try diluting it more thoroughly next time around before taking any readings.*

Then, you need to decide how to add more of whatever’s missing.

• Test your soil.
• Add nutrients to the soil.
• Change your light cycle if you have a grow light.
• Use fertilizer or a soil amendment (a substance that improves the quality of soil) to increase fertility and improve growth.

You can use organic amendments such as composted leaf mold, worm castings and composted cow manure to improve drainage and add nutrient-rich material to your potting mix or garden bed when building new beds from scratch; however, it’s important not to use added organic matter in excessively wet soils because it will not provide adequate aeration for roots.[11]

For nitrogen, potassium and magnesium deficiencies, you may want to give your plants a nutrient boost that’s high in the needed nutrient(s).

• Nitrogen deficiency: This is the most common deficiency, especially during the vegetative stage. Leaves will turn yellow or brown, and might have a red or purple tinge. The plant may also appear stunted or wilted—and if you’re growing outdoors, growth may be slow and stunted altogether.
• Magnesium deficiency: This is most likely to occur in the flowering stage of your marijuana plants’ lifecycle. The leaves will turn yellow with brown tips; they may also develop white spots on them.
• Potassium deficiency: Potassium deficiencies are usually seen when your plants are flowering—although they can happen at other points in their growth cycle as well.*

You can also switch fertilizers if yours is not meeting the plant’s needs.

The next thing you should do is determine whether the plant needs more of one nutrient or if it’s lacking a number of them. The best way to do this is by taking a soil sample and testing it in a lab or sending it out for testing.

If your plants are growing in hydroponic grow systems, then you’ll need to add nutrients directly into that system. But if your plants are growing in soil, then it’s time for some good old-fashioned gardening knowledge: You’ll need to know what kind of soil you have (loam? clay? sand?), how much water the area gets each year and which nutrients those types of soils lack before adding any fertilizer or other nutrient-rich substances like compost or worm castings (which can be very good at providing both nitrogen and phosphorus).

If your plant needs more nitrogen, then adding compost will likely do the trick; but if instead they need phosphorus (“P” on most nutrient charts), then adding blood meal will probably help. If there are yellow spots on only part of the leaf—typically toward its tip—then this could be due either to overfertilization or underfertilization; thus, checking with an expert before trying anything else would be wise.

Recommended products are Foliage Pro by Fox Farm and Flawless Finish by General Hydroponics.

To correct a nitrogen deficiency, we recommend using Fox Farm’s Foliage Pro. This is a high-nitrogen fertilizer that will help your plants grow strong and healthy.

If you have any yellow spots on your weed leaves and they’re not caused by over or under watering, then it’s likely that you have a magnesium deficiency. You can find out if this is the case by testing the pH of your soil with a PH tester or by using pH Up & Down products like General Hydroponics’ Flawless Finish.

Switching your light cycle may help too (12 hours on/12 hours off)

If you suspect your problem is related to light, try setting the lights to a 12-hour on/12-hour off cycle. This is what cannabis plants naturally prefer and will help ensure they’re getting all the light they need. You should also make sure that all of your plants are on this same light cycle—if one plant is getting more or less sunlight than another, it can throw off their growth patterns.

In all cases, your plants’ needs should dictate how you care for them—and that includes what nutrients they receive. Whether the yellow spots on your plants are caused by a lack of nitrogen, potassium or magnesium, the best way to treat this problem is through water-soluble fertilizers or foliar sprays. If you’re unsure about what to do next, we recommend contacting a professional who specializes in helping cannabis growers solve these types of problems. This can be very helpful if you need a holistic approach that considers all aspects of plant health and wellbeing (including light cycles).