It’s been an unusual season to say the least!
Having made plans to avoid blossom end rot, blight and a host of other problems and diseases, I felt quietly confident that I was about to experience the most successful season ever!
Well, “many a slip twixt cup and lip” was a saying my Grandfather often used, and unfortunately the unforeseen happened – dull weather for around three months at the most crucial time of the season!
I did learn an important tip about light levels and feeding.
- When light levels are low, tomato plants transpire less, so feeding can be increased.
- When the weather is warm and bright, plants transpire more, so feeding should be reduced.
Why – and what is transpiration?
Transpiration happens when water evaporates from leaves and is replaced by water absorbed by the plant’s roots.
The more water that is absorbed by the roots, the more food a plant takes in.
During bright sunny periods of weather, plants absorb more water/food. This means there is a danger of over-feeding, so the amount of nutrients we give our plants, should be reduced.
When the weather is cool and cloudy, plants absorb less water/food so under-feeding is a possibility and nutrients can be increased.
I’m not suggesting that every time the sun goes in we dash out and feed our tomato plants, but during periods of consistent weather, bad or good, we may be over or under-feeding without realising.
Tomato Plants & Circulation
Something else I have become more aware of this season is the sensitive vascular system tomato plants have (their plumbing) and how easy it is to clog-it-up!
This relates directly to over-feeding and the possible build-up of minerals in a plants system, causing poor circulation and toxicity. Water can evaporate from the leaves but the mineral nutrients remain in the plant. The result is similar to a central heating system – the pipes become clogged-up and the system becomes less efficient or even stops working.
In humans this could be compared to blood clots or (with nutrient build-up becoming toxic) blood poisoning!
Hydroponic growers are able to measure the amount of food in the water they use with an EC meter. Soil growers have to be careful not to be too generous with mineral nutrients.
As always, it is better to under-feed rather than over-feed for the reasons above.
Seedlings should be given very little water – almost to the point of wilting! That’s the practice of some growers according to an old tomato growing book called “Tomato Culture” by W.W. Tracy – you can Google it.
Of course you will need to be careful not to leave thirsty seedlings in full sun and dry soil if you are at work all day. However, it’s a fact that too much water or even a moderate amount will prevent a healthy root system developing in seedlings and young tomato plants.
Another point I would like to mention is about the old subject: “roots need air” but they need more of it than many people realise – it surprised me too! There are now air domes available to sit in the bottom of a large pot under the soil into which air is pumped – just like an air stone in a fish tank but for your roots not your fish!
My suggestion for next season is to create as many air pockets in the soil as possible with perlite and other growing media such as coconut/coir. Also, make sure that water can drain away easily – it is better that less water is available than too much which can make the root system unhealthy.
That’s why the autpot system is so useful (see last week’s newsletter) – it gives the correct amount automatically!
Some soil mixes also contain friendly microbes that attack bacteria and fungi that are harmful to plant roots – these are called soil inoculants and are an extra guard against root disease – often caused by over-watering.
That’s it for this season – thank you very much for all your comments and tips.
I look forward to next season, which will be the best ever (unless my Grandfather’s saying has anything to do with it!).
I may send out the odd email over the winter period, but the newsletter will begin again in February.