|The main reason for bottom end rot is poor flower pollination and lack of growth hormones ... and here's how I want to prove it!|
|I don't believe in the common theory that bottom rot is caused by lack of calcium for these reasons:
Perhaps you have found this page through a link to previous pages published in 2002 or 2005 on my biodynamic methods of growing tomato without irrigation (not a drop of water except for rain ... not even at transplanting time). If you need to review my previous pages ... here are the links:
In 2007 further progress is being made. I must thank Michael Phillips, the author of the book "The Apple Grower" - A Guide for the Organic Orchardist [ISBN 1-931498-91-1] - particularly interesting is page 130 where fruit thinning is discussed.
Apple trees develop a huge amount of blossoms ... and it is obvious that not all flowers can develop into a nice fruit (or the tree would collapse under the huge fruit weigth). Do you know that a single apple flower needs 6 - 8 bees' visits to be fully pollinated? - which is very unlikely and therefore most flowers and fruitlets drop. The apple grower will wait a few weeks after pollination and start removing (thinning) fruit. Not only you get much larger fruit by thinning, but most importantly you give back strength to the tree. Apples invest this extra-strength in the bud formation that will bear fruit the following year.
We believe that tomato vines also gain strength by reducing the number of fruit that fully develop. Because virtually all tomato flowers get pollinated and turn into fruit, I have been thinning flowers, up to 2/3 weeks before the fruit is formed.
Depending on the variety, tomato vines develop clusters of flowers counting 6 to 20 (sometimes up to 50 per stem in cherry tomato). My Kenosha Heritage variety tipically produces a cluster of 6 - 10 flowers in June, but up to 20 in July.
In June I start thinning the flowers (nipping the smallest flowers with my nails) and I only leave 4 flowers per stem for pollination. As I'm writing this page (in July) I'm observing much larger clusters and much larger individual flowers developping on the stems. This should prove that the vine is reinvesting the extra strength by producing larger flowers and stronger fruit stems ... in expectation of larger fruit?
I only save the largest flowers and reduce the number of flowers per cluster to 6. This practice has the main objective to obtain strong, large flowers that will perform a full pollination. Again, cross-referencing to what happens to apples that are not properly pollinated ... the trees drop them! Likely the tomato vine can tell if the fruit is not fully pollinated and will not provide the plant hormone that leads to fruit ripening. Bottom end rot may be the consequence of lacking plant hormone. The vine does not invest any energy in ripening a fruit that is not fully pollinated.
Also, be aware that most tomato varieties are self-pollinated (the flower pollinates before opening - that is the reason why you can grow several different varieties close to each other and cross-pollination is rare). Proper ventilation shakes the flowers and allows for a better pollination. The rare flowers that don't pollinate, don't develop fruit at all, are usually at the bottom of the vine where the ventilation is poorer.
During the 2009 growing season I have inspected about 70 Kenosha Paste vines with an avarage of 20 tomato each - on an estimated crop of 1400 tomato, I found 2 fruit with bottom rot (0.14 %) by August 20. The two affected tomato are a double fruit (beef heart shaped).
Here you go: Bottom Line on how to Prevent Bottom End Rot
How do I select the vines for seed saving purposes - which vines are producing the seed for 2008?
I save seeds of three varieties of tomato. You must keep the vines quite far apart if you want to prevent cross-pollination, which will eventually lead to a different fruit.
Certainly you don't want to be surprised with a much different fruit next year!
In addition to the Kenosha Heritage Paste Tomato, I also save seeds for Kenosha Tomato (SSE Tomato 810) and de-hybridized Sun Gold Sport that we call PlumGold.
The perfect fruit for perfect seed
You may have read on one of my past pages that the shape of the fruit correlates with the chance of developing bottom-end rot. Fruit with a flat bottom is more likely to rot than fruit that is heart-shaped. I find both shapes on the same vine but will select the heart-shaped fruit for seed saving.
The next challange is the shoulder crackings that attract fruit flies (and eventually lead to rotting before the fruit is fully ripe). This August 2007 we had a record rain fall in Kenosha - in addition to the already high humidity of our lake shore air. Therefore this year I'm finding more shoulder cracking than last year on some vines. But some vines have no shoulder cracking - a good candidate for seed saving.
To keep the diversity of this Kenosha Heritage tomato, I always select the best fruit from 5 different vines. In the past I would then mix the seed. This year I shall save it separately and document the results obtained with the 2008 vines.
|2008 seed saving
Two of the five tomatoes selected for seed saving in 2007 produced seed that did not germinate well, therefore I'm not saving seed off those vines. I'm very happy to report "zero" bottom rot on all vines K1 and K5, while K3 produced a few tomatoes with bottom rot ... but very few compared to years ago.
I also look for tomato with minimal cracking ... therefore I select my fruit for seed saving from vines that show consistently little or no shoulder cracking PLUS of course "zero" bottom rot.
Pictures of the latest fruit selection on this page