Top tips to protect your grow against extreme weather conditions

cannabis plants are susceptible to various environmental stress factors, including summer storms, which can cause both immediate and long-term effects on their overall health. While some damage may be unavoidable in extreme weather conditions, a combination of planning, protective measures, and quick action can help minimise the impact of these phenomena on your outdoor cannabis grow.

Sun, heat, long days, and lots of light. Summer is the best time to grow cannabis out in the open since the conditions are ideal for plants to reach maturity. But those beautiful sunny days can sometimes be accompanied by heavy rains, electrical storms, or even hail. And many growers are unsure about what to do with their cannabis plants in these circumstances.

Heavy rains can cause physical damage to crops, so protection is definitely required. However, the real threat is mould: after heavy rainfall, night temperatures can drop and create the perfect conditions for spores to germinate and spread. And there’s almost nothing you can do to cure a fungal infection once it sets in. Therefore, preventive measures are key.

The best way to protect your grow from these pathogens is by choosing strains that are resistant to fungi. Otherwise, there isn’t much you can do since the climate cannot be changed. Covering the plants is not usually effective because, when it rains a lot, the ambient humidity is so high that condensation continues to reach the flowers – and, by covering them, the airflow is reduced, which can actually make things worse.

But rain can also cause nutrient deficiencies, root rot, overwatering problems; and, depending on the growing medium, fluctuations in the pH of the soil. Here you will find some tips to protect your outdoor cannabis grow from heavy rains or intense gales.

Possible damage to plants

Before taking any action, let’s have a look at what your grow can face when a summer storm suddenly sneaks up on it:

• Physical damage: The strong winds associated with storms can cause cannabis plants to bend or break, which can significantly hinder their growth and yielding potential. Broken branches and stems can also become entry points for pests and diseases.
• Uprooted roots: Severe storms with strong winds can uproot cannabis plants whole, causing their death. Even if the plant is not fully uprooted, damage to its root system can have detrimental effects on nutrient absorption and overall health.
• Flooding: Heavy rain during storms may cause flooding in the grow area. Cannabis plants are sensitive to waterlogged soils, as their roots can suffocate and end up rotting away. Excess moisture can also increase the risk of fungal diseases.
• Soil erosion: Heavy rains can wash away the top layer of the soil, leaving the roots exposed and affecting the stability of the plant. This can also lead to nutrient depletion and reduced water retention capacity in the soil.
• Hail: This is another potential hazard during storms that can damage leaves, stems, and shoots, causing physical injury and creating areas where infections can proliferate.
• Humidity and mould problems: Storms can generate high levels of humidity. If these last for a long time, they can create a favourable environment for the growth of fungal infections that can spread rapidly and cause significant damage.

How to protect your cannabis plants outdoors

To mitigate the potential devastating effects of storms, it is important to take preventive measures such as providing the plants with physical support, choosing protected planting sites, or applying techniques like pruning or training. Regular monitoring of the plants, especially after storms, will help you to identify and address problems quickly. Here are other measures that you can also put into practice:

Watch out for the weather forecast

This is our first top tip, as well as the most obvious (although some growers still don’t seem to get it!). It is absolutely essential to stay ahead of the game by paying attention to the weather forecast. Knowing when inclement weather is coming can help you prepare and take preventive measures. Investing in a reliable mobile app or weather station provides real-time updates and information on temperature drops, heavy rain, strong winds, or possible frost.

Adjust the water consumption

This is simple: if your plants get more rain than usual, adjust the watering levels, since too much water can drown them and cause the roots to rot. Nobody likes a waterlogged grow, and neither do your plants. Even if they are covered or in a greenhouse, humidity levels can increase, and moisture can affect the amount of water that they need.

Create protective structures

When you choose the location for your grow, opt for an area that provides some natural protection against the wind, such as near a wall, fence, or other structures that can act as windbreaks (for instance, natural barriers such as surrounding hedges or shrubs). Having said that, the best thing you can do to protect your crop from the elements is to provide it with a roof. The ideal option is a greenhouse, as these are designed so the plants are exposed to the same amount of light as if they were outdoors whilst also being protected from the rain and wind. Perhaps your plants are planted directly in the ground, and you cannot move them to a greenhouse or under cover – if that’s the case, build a temporary shelter with a clear tarp and then remove it when the sun is shining.

Heavy-duty supports

Use sturdy supports like bamboo stakes or metal trellises to help the plants stay upright. These supports will prevent the plants from bending or breaking under the pressure of strong winds or the increased weight of wet buds. Emergency stakes can also be used: if a storm is coming and your plants are already set in the ground, you can stick them around the plant; but make sure they are far enough from the base to avoid damaging the roots.

Pruning and training

One of the best things you can do to prevent your cannabis plants from being damaged is to train them as soon as possible. Methods vary greatly, from Low Stress Training (LST) to gently tying the branches to avoid over-exposure to the elements. Or building a raised bed or box and putting a net on top to limit the height whilst promoting horizontal growth. Placing a net on your plants won’t protect them from the rain, but it will keep the wind at bay. Trimming the excess foliage and removing weak branches can also minimise the risk of breakage.

Use of preventive fungicides

Regular application of preventive fungicides containing Bacillus subtilis as an active ingredient can help prevent fungal infections that occur after periods of heavy rain. This bacteria produces antibiotics that suppress fungi, which can in turn minimise harmful outbreaks of botrytis, downy mildew, and powdery mildew. This product is most effective when used preventively, so start applying it in the vegetative stage to ensure that the Bacillus has the opportunity to colonise the plant before periods of frequent rains.

Gently shake the water from the plants

While there’s little that growers can do to protect their crops during a storm, it is quite simple to gently shake the plants after an intense rain event. This may seem like a useless activity, but it does actually help decrease the amount of water on the plant and the time it takes to evaporate.

Ensure proper drainage

And last but not least, a good drainage system is essential to protect your cannabis plants during storms. Water excess can lead to root rot and other humidity-related issues, so make sure the soil has good drainage and consider installing channels or ditches to divert excess runoff water.

In summary

Protecting your cannabis grow against extreme weather conditions requires a combination of the appropriate preparation, technology, and growing techniques. Investing in physical protection systems, strengthening the plants, managing the water properly, or being prepared for hail and strong winds, are all crucial steps to ensure the health and productivity of your plants. The key is in anticipating and responding quickly to changing climate conditions, thereby ensuring a successful and high-quality harvest.