How does low humidity affect growth?
 

I live in Southern California, where we only get a plenty of humidity during the winter, at night, and in the morning. During the later part of the growing season, it can get pretty dry. Does this have negative effects on plant growth and the eventual bunch size? The normal growth rate is supposed to be 1 leaf per week, right? My plants aren't even growing nearly as fast as that. If so, how much does low humidity slow down growth?

Re: How does low humidity affect growth?
 

I can't really speak for CA weather since I'm in Milwaukee, WI. But I can say I have noticed that higher dew points really enourage faster growth. Lately, even with temps in the 70s, the air has been dry, and growth has been pretty slow. When de wpoints wer ein the 60s and 70s I was getting a leaf a week. Now it is much slower. Plus the leaf eges dry out, even with even watering.

Eric

Re: How does low humidity affect growth?
 

I know for a fact that the average humidity varies throughout the summer. It's on average 50% during July, and at that point my plant was putting out a leaf a week. It then started slowing down during August as it dropped. It gets really dry sometimes in the fall when the Santa Ana winds pass through. So I guess that's partially to blame why my plants are growing slower.

Re: How does low humidity affect growth?
 

Re: How does low humidity affect growth?
 

Bananas grow fine here where humidity is usually below 10%

Re: How does low humidity affect growth?
 

Andreas, I doubt it is the humidity alone. It's not summer anymore, and the hours of daylight are decreasing and the temperature is dropping -- both affect rate of growth. I wouldn't use "a leaf a week" as the yardstick for growth in California. I only get that in young plants (leaf production slows down with plant age) under optimal conditions here in Ventura, where a warm summer day is mid 70's. If it makes you feel any better, on my fastest bananas, I'm only getting a leaf every 1.5 weeks right now, and for many it's more like one every 3 weeks. I'm sure our buddies in Florida and the tropics will scoff at that, but hey, but when your daytime highs are in the 60's and your nighttime lows are in the 50's, you need to change your expectations. Get ready to really lower your expectations for winter, when we have lows in the 30's and highs in the 50's. On my slower plants last winter, it was taking 6-8 weeks for a new leaf.

Re: How does low humidity affect growth?
 

Alright. I guess that these first two plants I can just use to get a feel for growing. And another question: Should I put a tarp around the base of the plants to keep out rainwater which can saturate the soil and cause root rot?

Re: How does low humidity affect growth?
 

Yes. It can only help.

Re: How does low humidity affect growth?
 

I see from your picture (1st image), that you are missing a layer of mulch around your plants (2nd image).

Re: How does low humidity affect growth?
 

I should probably add some, although winter cold isn't a real problem here. I'm going to put tarp around the bases of the plants during the winter to keep out the rain.

Re: How does low humidity affect growth?
 

Mulch helps to create a more uniform level of moisture in the soil, keeps the soil temperature more constant (in summer and winter) and creates a favorable environment for beneficial microorganisms.

Re: How does low humidity affect growth?
 

Just added some cocoa mulch today. Also fertilized and watered.

Re: How does low humidity affect growth?
 

The physiological answer is that during time of low humidity the stomata will close. Water moves through the plant along a gradient of water potential. If the difference between the water potential in the leaf and in the air is too great the plant will shut it's stomata. No open stomata, no carbon assimilation, no growth.

Re: How does low humidity affect growth?
 

Would spraying down the leaves with water help?