3 Signs of Plant Stress

There are a number of things that can cause a plant to get stressed – unfavourable weather conditions, inadequate water & nutrients, pest damage, diseases, lack of sunlight and so on. Recognising signs of stress is a useful skill to have and will help you keep your plants well cared for.

  1. Wilting
    When a plant wilts, there are generally four possible causes: not enough water; too much water; too hot; or root damage. Root damage could also be due to pests like cabbage root fly or a fungal disease such as club root.

    When making a diagnosis, checking the water levels in the soil should be your first step. The very top 1cm layer of the soil may be dry, but when you push your finger into the soil you should be able to see that beneath that top layer there is plenty of moisture. If you find the soil is dry and crumbly it’s time to water your plants (and please don’t be scared to do this in the mid afternoon sun – if your plants are wilting and they need water, then it’s best to give it to them sooner rather than later!) However, you may find that the soil is actually too soggy and waterlogged (this is common when growing in pots and containers). If this is the case, try to find a way to allow the soil to dry out a little – this could be by raising pots off the ground onto bricks or pallets so that the water can drain, or it may be by creating a little channel for water to drain away.

    If water levels are ok, it could simply be that the plants are too hot. This can often happen in greenhouses, for example. Try casting a little shade over them, open greenhouse doors/windows, or if they are growing outside simply wait until the cool of the evening to see if the plants perk up.

    If you’ve ruled out water and heat, then we would suggest carefully digging up a plant to inspect the roots and see if you can see any damage. Unfortunately it is difficult to revive plants with root damage, but at least you’ll know what’s wrong so that you can protect them the next time!

  2. Leaf Discolouration
    Keeping an eye on the leaf colour of your veg plants will really help you to care for them. As a general rule you’re looking for a vibrant green (obviously some plants will have different coloured leaves – red/purple – but you get the gist!) and any discolouration, whether it’s a pale green, yellow hue, white papery patches, brown patches and so on, is an indication that the plant is struggling.

    More often than not this will be caused by a lack of water, a lack of nutrients, cold or windy weather or a fungal disease. At this early stage of the season, it is less likely to be a fungal disease and more likely to be weather conditions or water/nutrient intake.

    Check the water levels – if there is plenty of moisture in the soil and plants are still struggling, then decide whether they are more likely to be struggling with weather conditions or with a lack of nutrients. If the plants are exposed to cold/wind, then do your best to protect them by putting together a makeshift polytunnel, covering them with horticultural fleece or a cloche tunnel. If you suspect a lack of nutrients, perhaps if you didn’t add any compost when planting, then applying a liquid feed once or twice a month will help. You can also use wormcast fertiliser, and it is a really good idea to mulch plants with organic matter or compost if you can as this will help replenish the soil.

  3. Bolting
    Bolting, also referred to as ‘running to seed’, ┬áis when a plant that should be in the throes of producing lots of lovely green leaves instead forms a flower head and subsequently seeds, like the broccoli plant pictured. This is the plant’s bid to save itself by reproducing earlier than it normally would. One a plant has bolted you can’t return it to its former leafy state, so prevention is the key.

    A plant will bolt during particularly hot or dry conditions, so it is important to keep plants well watered and cool. Adding a mulch (basically putting a layer of organic matter on top of the surface of the soil) around plants really helps to keep the soil a little cooler and more moist.

    Some plants are more prone to bolting than others. these include: coriander, lettuces & leaves, wild rocket, and pak choi