Hello Oldi,
@ Day length:
Sounds are interesting, we can then compare our results because I think also about a trial with short day length. I'll take probably Cormels or smaller tubers so that the plants are not as big and thus easier to the cover are. Young plants produce more leaves, but I hope that they otherwise similar to react to the amount of light as larger/older plants do it.
@ Factor heat:
I have several IGs in the garden and therefore do not have a single leaf records how long green or is ok. A normal year the plants keep all the sheets until the autumn. This summer just one tree has lost a hand, it is still off, is yellow, has shrunk, and is no longer ok. It is the first and it came in May. The weather was why it had Brown areas pushing out cold and rainy and the shaft is shorter than on the sheet No. 2.
Last night I have my plants (with measuring tape
) watched on. All have three or four leaves. They are different per plant big but the order is different (A plant has a large leaf-1, at plant B sheet 1 is much smaller, and so on). The size may be related with the temperature in the driving, I have not thought about and have not recorded when the leaves are driven out. I have recorded temperatures.
Usually the warmest period of the summer weather is with us in the period of late July to mid-August. If heat is the most important factor, this may be already the explanation for the rapid growth phase in August what I have observed several times. Then there is probably nothing else to do than to buy a greenhouse in order to have a better success with the plant!
@ But there is still something:
Many plants that late start to grow, make usually at the same time two new hands after the second hand. Although the two hands usually come in early August I think not so correctly that the heat is the key factor here. Perhaps there is a relationship between Tuber size and number of sheets?
Greeting Olvi