Leaves and Nutrient Deficiencies
When it comes to tomato plant leaves and nutrient deficiencies, they say that tomato growers with poor eyesight are the happiest because they can’t see the various spots and markings that appear on their tomato plant leaves each season.
it is very common for plants to show all sorts of deficiencies on their leaves, especially at this time of the season – you may have some strange looking markings on your plants too!
Phosphorus, potassium or magnesium deficient are very common – especially on the lower leaves.
Here are some examples on my plants – from previous seasons.
Tomato Plant Leaves and Nutrient Deficiencies
Some leaves may be affected by all three mineral deficiencies at the same time!
To make it even more difficult to diagnose, some varieties display these deficiencies in slightly different ways. That’s one reason why professional growers will get to know a variety over several growing seasons and be able to get the very best results from a variety.
For example, I know Red Alert very well, but when it comes to some of the new varieties, there is some trial and error involved.
So what can you do when your plants leaves show nutrient deficiency? The answer is … not very much!
It’s often the case that the deficiencies were caused by temperature variations (poor weather) when the affected leaves were forming.
Or, the nutrients have been taken from the lower leaves and used by the upper leaves … the growing tip always gets preference over lower leaves and takes the minerals that are stored in them. (aka translocation).
Lower leaves often turn a pale green or yellow colour because nitrogen and magnesium have been removed to the growing tip.
What to do
Remove affected lower leaf branches that are losing their colour or yellowing- it’s the new growth that matters and it’s quite likely that the leaves at the top of the plant will look very healthy.
Magnesium – Foliar Spray Benefits
One way to get plants to grow faster (and healthier) is to increase their rate of photosynthesis.
This may be done by making sure that leaves are a dark green colour – the darker the colour, the more light is absorbed, and therefore, the process of photosynthesis works better. To absorb more light is helpful when light levels are low in a poor summer.
How to get dark green leaves
Magnesium is used in the process of making chlorophyll (the green pigment in leaves) and so a foliar spray of magnesium will help “green-up” leaves and make them a darker colour – they will attract more light.
Also, magnesium is needed by tomato plants in larger amounts around the early summer, so a foliar spray with magnesium is useful for this reason too.
Double Stem Technique
Double Stems and Side Shoots
Some tomato growers will allow a side shoot to develop and become a second main stem.
This is known as the “double stemming technique” and will provide more trusses before the plant grows out of the greenhouse roof!
That’s assuming we have a good enough Summer and time enough to grow more tomatoes from one plant before the Autumn weather begins.
It’s best to use this technique with cherry varieties that are quick to mature if you are in the UK – and especially if growing outdoors.
This side shoot could be left to grow and create a second stem if required … otherwise, it’s best removed.
Some gardeners who live in areas of the world that have longer seasons than in the UK, don’t remove side shoots on their tall varieties. This means they may have at least six or seven main stems!
In a long season of good weather, a tomato plant will perform and produce a fabulous crop – In the UK, it will probably run out of steam and produce smaller trusses than normal.
That’s it for this week – don’t look too closely at those leaves!