June 29, 2017

Good morning, I am so hoping that the hottest weather is behind us. As a gardener I have never experienced that kind of heat. I am grateful that I had managed to get everything mulched this year, otherwise I am not too sure how I would have coped. 

It was interesting to see how the veggies reacted to the heat. The results began to show shortly after the second bout. All of the larger leaved plants such as the cucumbers and summer squash started to drop all of their older leaves. Even though a lot of these leaves looked perfectly healthy only a day or two before. This leaf drop was a means to help the plants to partially control leaf transpiration. Plant transpiration is the means that plants suck up water through the roots and then vacated through the the leaf stomata. Small holes on the lower sides of the leaf that evolved for this purpose. This water flow is what is necessary for all the plants biological functions. 

With increased temperatures there is an increased flow. Once the heat gets to great the leaves begin to wilt, because the water flow is greater than what the plants can provide. This is a means that the plant can control water flow.  With out the crown cover provided for by the foliage, the plants and soil around the plants begin to heat up. As the temperature rises the wilt increases. Without the crown closure the leaf stems and the trunks of the plants can become sun scalded. In the worst cases the sun scalding can kill leaves or plants. This is where the bed mulch at least lowers the soil evaporation. By capillary action, without mulch to inhibit the soil water flow to atmosphere, there would be even less water available to the plants. 

This wilting puts a great stress on the older leaves and they soon expire. This in its self helps the plant to conserve water.

It was very interesting one year up in Oregon during a drought, the trees experienced an early fall color change at the end of August and early September. Here again it was a means that the trees were limiting water loss. Once the color change of the leaves there was an early falling of the leaves. Thus the only transpiration was through the bark. Much lower rates but there none the less.

Sooo with this said, I tried to help these plants through this past heat thingy. I covered all of the plants that I could with fabric. The okra was the exception, although it seemed to enjoy the heat by continuing to grow where everything else was shutting down. The drip system was turned on during the heat of the day to help augment this increased water demand. Even so the older leaves are giving up the ghost.

For me, some of this heat induced leaf drop could be caused by my root knot nematodes. These vermin can and do cause the plant to not be able to take up this ever so valuable moisture. There also has been an heat induced Chlorosis (yellowing of the leaves). Seeing this, some fish emulsion with iron chelate has been given to the plants. There has been a very rewarding response to this with abundant new bright green growth. Hopefully flowering will follow.

Ah yes all things must pass!!

This week I harvested chard, kale, green onions, carrots, cucumbers, and beets. In storage there is garlic and bulb onions. Please ask for about availability.