It is the time of the season when almost every question I receive about tomato problems is about either:
- Rotten patches on the underside of tomatoes.
- Flowers drop off of their stems.
The first is Blossom End Rot which is caused by calcium deficiency.
Plants roots have been unable to absorb enough calcium (for some reason) and as the tomatoes swell, there isn’t enough calcium to complete the growth of the “blossom end” which is the underside of the tomato.
The remedy is simple – foliar spray with Chempak Calcium just after the first flowers have set and you have pea-size fruit.
Watering correctly will also help, but it is almost impossible to keep compost “just moist” in container-grown plants.
The second problem is Blossom Drop which is caused when flowers fail to pollinate.
When weather conditions are too dry or too humid for pollen to be effective.
The remedy for this is to spray/mist with water and tap plants gently when the air is dry and to tap plants regularly when the weather is damp.
A vibrating tooth brush or shaver (battery operated of course!) could be placed under the flowers to aid pollination also – similar to the buzz of a bumble bee.
If you have a question about tomato growing that you would like to ask please email me at: firstname.lastname@example.org or via the question box on the right.
Blossom End Rot (BER) is a condition caused by a lack of calcium.
Calcium is used to build the fleshy wall – just inside the skin of a tomato – and when the calcium runs out, a black mark appears on the underside of a tomato leaving the fruit uneatable.
I once grew a plant called yellow pear where almost every tomato was affected by BER!
If you are growing tomatoes in containers, especially pots, it is extremely difficult to avoid BER because in order to do so, soil has to be kept constantly moist in order that plant roots have full access to the nutrients in the soil.
Dry soil means that no nutrients are available because roots can only access nutrients with moisture/water.
In hot weather it is impossible to keep soil “just moist”, so to avoid BER other methods can be used.
Foliar feeding with calcium is one of the best ways to add calcium into a plant because it is quickly absorbed.
Some minerals travel around a plant to the point of need more quickly than others. Unfortunately, calcium is a “slow mover” so feeding by roots takes time to reach the spot.
However, if calcium is applied regularly to roots (in small amounts) it can help greatly to avoid BER.
Not all tomato food contains calcium.
I recommend Chempak Calcium to be given as a root feed and foliar spray along with the addition of magnesium on a weekly basis from flowering.
Over-feeding before flowering can delay the production of flowers and fruit.
My plants have been rained on for the past two days, almost non stop!
However, they are under cover, albeit a temporary effort, but it will keep them from wet leaves.
Wet leaves for more than a day or two, will make plants vulnerable to fungal disease … the dreaded “tomato blight” which cannot be cured – only controlled.
My outside plants are all under cover of some kind … it may not look very pretty but it works.
Get some plastic sheeting and with a few garden pegs you have a temporary cover, and hopefully tomatoes too in a few weeks time.
If you suspect that your plants have tomato blight, please follow this link tomato blight.