Pioneering Hydroponics

Since 1976

Why are Plant Leaves Curling Up? And Other FAQs

Plants tend to present similar symptoms when it comes to plant diseases, nutrient deficiencies, and other similar issues. If your hydroponic garden is looking unhealthy, there may be serious underlying issues that need to be addressed as soon as possible.


Why are Plant Leaves Curling Up?

Plant leaves curling upwards, it’s usually a sign of something wrong with the environment of the grow room. It could be due to not enough air exchange, windburn, or lights being placed too close to the plants. But what about when leaves curl down?

When plant leaves curl downwards, plants are usually trying to conserve moisture. It could be down to either overfeeding or overwatering. Should the leaf margins be curling down, your plants likely have an issue in the root zone. This can be caused by overfeeding, low oxygen levels in the root zone, nutrient temperatures, or diseases/pests that cause the leaf tips to curl.


Why are Plants Losing Colour?

When plants lose colour either across the top, middle, or bottom parts, it’s usually due to underfeeding or a nutrient deficiency. If the larger leaves start yellowing from the ends towards the main vein, your plants likely have a potassium deficiency.

A dark purple tinge and a purpling stem on the large, green leaves tend to point towards a phosphorus deficiency. A Nitrogen deficiency tends to cause the tips of the larger leaves yellowing evenly towards the stem.

Micronutrient deficiencies usually appear on new growth first, with magnesium being the only exception. Magnesium deficiencies show symptoms on the older leaves. These turn yellow while the veins remain green, with brown rusty spots or burnt-like patches appearing as the deficiency progresses. 

A calcium deficiency will translate to young leaf necrosis, with their tips being brown and crispy. The older growth shows necrotic and brown spots. An iron deficiency tends to appear as an interveinal colour loss.

Are there other reasons for colour loss?

Leaves can start yellowing and losing their sheen if they experience over transpiration. Rust spots appear after a few weeks, with the stomata stopping their function and leaves dying off. Lack of oxygen at the roots will cause plants to grow slowly and droop. Other reasons can be:

  • Wind (or air) burn.

  • Nutrient solutions with very high temperatures.

  • Light being too close and causing bleaching.

  • Cold nights.


Why are the Leaves Damaged?

New growth is always a good indicator of the present state of your plants. If your plants are experiencing leaf drooping, it’s not necessarily a worrying issue. To help them deal with the intense lighting in the grow room, you should always make sure to:

  • Have the right pH and EC.

  • Keep temperatures between 18℃-21℃.

  • Provide high oxygen levels.

If plant leaves are too small, you may be overfeeding your plants. You may also notice smaller and narrower leaves developing under fluorescent lights or dry environments, and bigger and wider leaves developing under sodium lights or humid environments.

Any twisted or seriously misshapen leaves can be a sign of calcium deficiency, unstable genetics, or excess chlorine in the water.


Why are the Roots Dissolving?

Damping-off can happen if seedlings or cuttings are in a humid propagator with still air. This can quickly become root rot, as the stem becomes soft and watery. This could be a sign of Pythium or other plant diseases, which need to be treated straight away.

Whether you only grow a few plants or you’re thinking about expanding your grow room, having the highest quality of hydroponic nutrients and grow room essentials is vital. Make sure to get in touch on 01695 554 080 or 01226 320 850 to know more about some of the UK’s leading brands in hydroponics.