Tomato plants are very sensitive (a bit like some of us!) and any changes that happen suddenly or conditions that become unfavourable can stress them – and we all know what stress is like!
This includes when roots reach the sides of a pot and realise that they only have so much room to grow. This has the effect of forcing them on to flowering and maturity. As long as they are potted up and don’t become root-bound, they won’t mind too much.
The technique of keeping plants in small pots to make them flower sooner, is called “forcing”. If over-applied will stunt growth and plants will produce a poor crop.
In contrast, a seed sown directly into the soil will have an unlimited area for its roots and will usually take longer to reach the fruiting stage – if it lives that long!
There are many causes of this kind of stress, including:
- Being moved outdoors overnight before being hardened-off
- Affected by diseases
Signs of Stress
Leaves that curl at the tips or turn away from the the sun are signals that something is wrong.
This photo shows severe curling at the tip of a tall variety – the plant is either very stressed or suffering from a virus such as curlytop.
The cause of wilting leaves may just be a lack of water – but could be something more serious like a fungal infection that stops-up a plant’s plumbing.
Leaf roll – when leaves roll inwards at the edges is very common and some varieties will do this by default. This is nothing to worry about.
However, if leaves curl upwards at the edges, that is a sign of stress.
Leaf discolouration is usually due to nutrient deficiency. It is very common to see a purple tinge on the underside of leaves which indicates that temperatures are a bit low and it is therefore more difficult for plants to absorb nutrients.
It’s best not to feed at roots when treating plants for stress but give a foliar spray (misting) with a tonic of some kind.
Shade from direct sunlight and keep warm, dry and out of the wind.
After a few days – if the plant is still in a pot, pot on to bigger home and add perlite to the mix. This will help the roots by adding air to the soil.
Nutrients and tonics such as SP Plant Invigorator and Liquid Seaweed Extract help boost their general health.
There are a number of stress relievers and plant boosters (organic too) in the hydroponic product range that can be applied to soil-grown plants.
So even tomato plants can suffer from stress and their leaves will let you know when they need help!