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How to Prevent and Treat Dry and Crispy Cannabis Leaves

Nothing warms a grower’s heart more than seeing their plants flourish. The opposite is true when they encounter dry and crispy leaves. Such a sight causes worry and concern. Are your plants ill? Will this damage your yield? Could they be dying? We created this guide to put your mind at ease. Learn about the causes and exactly how to treat it.

How to fix dry and crispy cannabis leaves.

Contents:

Healthy and vibrant cannabis specimens dominate social media feeds. These thriving plants display firm, dark green fan leaves with a waxy shine protruding from robust and sturdy stems. Every grower strives to achieve plants that look half as healthy. However, things don’t always go to plan.

Have you ever walked into your grow space to see dry, crispy leaves hanging on for dear life? It’s disheartening, and far from the luscious foliage depicted on Instagram. If your leaves are looking a little worse for wear, check out the guide below. We’ll cover every possible cause for the condition, and how to fix it.

What Causes Dry, Crispy Cannabis Leaves?

A problem-solver lies at the heart of every cannabis grower. A large part of harvesting a canopy of healthy buds involves a fair amount of troubleshooting along the way, from nutrient deficiencies to pest invasions. Dry, crispy leaves are one of these potential problems. This occurs when plants lose their moisture content, curl up, and feel fragile and crunchy to the touch. Several environmental factors give rise to this issue—nutrient problems, too much water, and excess heat are just a few of the common culprits.

Fortunately, we’ve identified solutions to all of them. Use the guide below to learn what exactly causes cannabis leaves to turn dry, and what you can do to rescue your plants.

Old Age

Cannabis plants don’t stay young forever. Dry, crispy leaves occur naturally towards the end of a plant’s life cycle. During the late flowering stage, as plants divert most of their resources towards forming resinous buds, you’ll notice some fan leaves start to dry and discolour.

Old age largely affects the lower leaves, but those higher up might also begin to lose their moisture content and luscious green appearance. If your plants are otherwise healthy, pest-free, and enjoying ideal temperatures, chances are they are simply getting old.

Fan leaves will appear particularly dry and frail during flushing—the act of restricting feeding around two weeks before harvest to improve the flavour of the buds. An intentional lack of key nutrients will take a toll on the foliage and often cause many fan leaves to fall to the ground.

Solution

As a natural phenomenon, you have nothing to worry about. Let nature play its course. Take a clean pair of pruning shears and defoliate the dried and dying leaves to improve canopy aeration and clean up the aesthetics of your plants.

Nutrient Issues

Cannabis plants require a balance of key nutrients to survive and thrive. These natural compounds play vital roles in cannabis physiology, from assisting with photosynthesis to facilitating tissue growth and flowering.

Plants require two key groups of nutrients: macronutrients and micronutrients. As their names suggest, plants require the former in larger quantities and the latter in smaller amounts. Most growers manage to supply their plants with adequate nutrients using either high-quality compost or supplements.

Despite this, plants can still exhibit deficiency symptoms due to pH fluctuations. If the pH of the growing medium becomes too low or too high, plants lose the ability to absorb nutrients. Low levels of molecules such as iron and magnesium—important for chlorophyll formation and enzyme synthesis—can lead to crispy, dry leaves.

A nutrient surplus can also cause dry and damaged fan leaves. Excess nitrogen can burn roots, causing the fan leaves to become extremely dark green and crispy.

Solution

Adjust the pH of your growing medium to restore a healthy balance. Cannabis plants thrive in a pH of between 6.0–7.0, whereas hydroponic plants prefer a pH of 5.5–6.5. Use a pH tester to determine the status of your soil. First, attempt to flush out the growing medium with pH-balanced water and test the growing medium again. If the pH level is still out of whack, apply pH correction products available at any growing store.

Also, consider adding mycorrhizal fungi to your soil. These beneficial fungi form a mutually beneficial relationship with plant roots, helping them mine for nutrients in return for sugars.

Overwatering

It’s no secret that cannabis needs water to survive. Plants use this precious resource during photosynthesis, to transport nutrients, and to keep them turgid and strong. Yet, as with everything, too much water does more harm than good.

Overwatering usually occurs when beginner growers take too much care of their plants—they see one speck of dry soil and begin to panic. A constant supply of water means fluid begins to pool in the soil. When plants take up too much water, cells within the leaves bulge and eventually rupture. This causes crusting at the tips and a crispy complexion. Not to mention, excess water creates a breeding ground for damaging fungi, and it flushes valuable nutrients from the soil.

Solution

Water your plants intelligently. A slight dryness in the soil is actually a good thing. As a rule of thumb, only water your plant again once the top five centimetres are dry. To keep better track of things, weigh your pots when they’re dry and again when fully watered. Wait for your pots to get close to their dry weight before watering again.

Pests and Fungi

Humans aren’t the only Earthbound creatures with a penchant for pot. Many different species of microbes, insects, and mould all enjoy savouring the taste of fresh cannabis plants. Aphids, caterpillars, and slugs all like to graze on cannabis leaves, whereas plant-parasitic nematodes prefer the taste of roots. Fungi will settle just about anywhere on the plant, as long as it provides them with their favourite conditions—dampness and humidity.

Cannabis plants can take a bit of pest damage, and the presence of a few insects indicates strong biodiversity within the garden. But prolonged and intense assaults can cause them a great deal of stress, possibly resulting in dry and crispy leaves.

Solution

Protect your plants! Different species require different tactics. Use predatory insects such as ladybugs, parasitic wasps, and praying mantis to keep pest species at bay. For a second line of defence, sow companion plants such as dill, sweet basil, sunflower, and lavender early in the season to repel and distract damaging insects.

Do you have a feeling your roots are under attack? Inoculate your soil with mycorrhizal fungi; their fine filaments—hyphae—tie down and trap gnawing nematodes. And what about that pesky mould? Simple. Keep your plants aerated with fans or a natural breeze. Avoid overwatering the soil and cover up your crop to protect it from downpours during flowering.

Excessive Heat

Heat has a tendency to make things crispy: bacon, toast, even our skin after too much time on the beach. Leave your cannabis plants exposed under the baking sun in a greenhouse or garden, and you’ll find their fan leaves take on this property, too. Intense heat will cause leaves to lose moisture, dry out, and shrivel up.

Solution

If you’re growing outdoors in a particularly hot region, be prepared to defend your plants from a heatwave. Keep some shade cloth and a few stakes on standby, and deploy a DIY setup if the sun beats down harshly for too long.

If you find your grow room becomes unbearably hot, use fans and air conditioning to bring the temperature down. You can even use a sensor and controller rigged up to an exhaust fan to automate this function.

Light Burn

Another pillar of plant life, light enables cannabis plants to create their own energy. Without light, you can say goodbye to cannabis buds altogether. Yet, too much light will burn the upper areas of your plant, causing leaves to crisp over and even damaging high-flying colas. If you let your canopy grow too tall, expect discolouration, dryness, and reduced yields.

Solution

Monitor your indoor grow closely. Move your light system up as your plant continues to work its way upwards. If you’re dealing with limited space, use LST and Sc rOG techniques to keep your canopy lower to the ground without sacrificing output.

LED lights are becoming more popular among cannabis growers. As well as being cheaper to run, these lights emit less heat and offer more room for error if your plants grow a tad out of control.

Treating Dry, Crispy Leaves on Weed Plants

If you notice fan leaves becoming crispy and dry, don’t panic! Take on the problem with a level head and remember what you’ve just learned. Revisit our guide, identify the prob lem, and utilise the correct treatment. If you act efficiently, you’ll rescue your plants, solve a horticultural problem, and become a better grower all at the same time.

Dry and crispy leaves don't just look bad, they can stir up quite a panic. But don't worry, check out our guide to discover every single cause and treatment.

Why are leaf tips brown, burnt, or yellow?

Leaves have burnt tips, yellow tips, brown edges… These are some of the most common symptoms growers see on their cannabis plants. It can be hard to identify the cause because a lot of different things can cause similar symptoms.

Today I’ll break down all the reasons you might see brown tips or yellow leaf edges. Get to the root of the problem and get back to green healthy leaves!

Nutrient burn is a common cause of burnt leaf tips, but not the only one!

1.) Nutrient Burn

There are a few possible causes for discolored leaf tips, but one of the most common is nutrient burn.

This happens when you are giving cannabis plant too high levels of nutrients. Usually, the first signs of cannabis nutrient burn are yellow or brown tips on leaves after increasing the overall amount of nutrients. As time goes on, the brown continues inward and the tips start curling up. The tips will be dry and easily break off with any pressure.

Nutrient burn is brown and appears on the tips of leaves and causes ends to curl up

2.) Light Burn

Plants can get light burn (sort of like a sunburn) even if the temperature is completely under control. The symptoms are usually concentrated close to the grow lights.

A lot of growers don’t realize that light stress (lights being too close) can cause yellow tips. This symptom is often mistaken for nutrient burn. You can tell the difference because the yellow tips on appear on leaves close to the light. With nutrient burn, the tips are usually brown and appear all over the plant.

Yellow tips from the grow light being too close (light stress)

Light burn can cause the leaves closest to the light to turn yellow or brown around the edges

If it keeps progressing, light burn can also cause the edges of leaves to start turning brown

Another example of light burn from the grow light being too close

3.) PH or Nutrient Problem

Certain nutrient deficiencies are often mistaken for nutrient burn.

Here are some common nutrient deficiencies that can also cause burnt or yellow leaf tips and edges. Nearly all of these examples were caused by Incorrect pH (the #1 cause of nutrient deficiencies).

A potassium deficiency causes the edges of leaves to appear burned

Another example of a potassium deficiency

A potassium deficiency is often mistaken for nutrient burn. One clue is the brown edges go in further that nutrient burn, and doesn’t affect tips as evenly.

A potassium deficiency can express itself in a few different ways

A copper deficiency causes dark leaves with yellow edges

A magnesium deficiency can also discolor the leaf edges

The best way to prevent nutrient deficiencies is to make sure you’re giving your plants the right type of nutrients and pH’ing the water to the proper level depending on your growing medium. But that doesn’t mean more is better. It’s important not to overload your plants with too high levels of nutrients.

Too Much Nitrogen (Nitrogen Toxicity) causes dark green leaves that often feel dry and crispy and get discolored edges

What about Calcium deficiencies?

It used to be that a lot of growers thought brown tips were caused by a Calcium deficiency. However, we’ve since learned that’s incorrect. Here is what a real Calcium deficiency looks like.

Calcium deficiencies don’t cause brown tips. This is a calcium deficiency.

Another example of a calcium deficiency (no brown tips). It mostly affects the middle of leaves.

4.) Heat Stress

Even if your grow light is a good distance away from your cannabis plants, they can still get stressed out by too much heat. Cannabis plants generally prefer temperatures under 85°F / 30°C, though some strains are more sensitive to heat (shorter, bushier strains are often more sensitive to heat than the longer, lankier strains).

Most plants are fine with a few hot days, but if it’s hot every day for weeks, your plants can really start to suffer. Most marijuana plants can handle a small heat spell, but they don’t want to live in a desert! Learn 5 secrets to controlling heat in the grow room.

Heat Stress can burn leaf edges

The following plant experienced 100°F (38°C) temperatures for several days during a heat wave. Burnt leaf tips doesn’t even begin to describe what happened to this poor plant.

An extreme case of heat stress

5.) Root Problems, Root Rot or Bad Watering Practices

Chronic overwatering can sometimes cause unusual deficiencies even if the pH is spot on, like this plant grown in muddy soil. The biggest sign that these symptoms are caused by overwatering and not pH (or something else) is that the plant is always droopy.

Another example of a deficiency that’s actually caused by overwatering (notice how this seedling is also droopy)

6.) Bugs or Pests

If you ever experience a big infestation, bugs and pests can cause a surprising number of symptoms including burnt leaf tips or edges.

Fungus Gnats are one of the most common. They look like tiny flies buzzing around your topsoil. Although a few fungus gnats won’t really hurt your plants, a ton of them will damage the roots, causing symptoms similar to other types of root problems. This can include brown or burnt leaf edges.

A bad fungus gnat infestation can cause a variety of symptoms

Leaves with brown tips, burnt tips, and yellow tips can be hard to diagnose because so many problems can cause similar symptoms. Once you know the cause it’s easy to fix, but if you don’t know it’s impossible! I hope this article helped you figure out what’s causing your symptoms so you can get back to growing.

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