Here is the deal, the last grow the temps got up to 84° for a couple of days {broke a/c} w/o Co2 and every one of these girls produced pollen sacks, I guess from stress.
Heat is definitely one of the environmental factors that can produce hermies.
But it is also genetics. If you don't know the heritage of your seeds, and want to prevent hermies - I would go to a reputable seed bank (there are several who are
sponsors here - Herbies and Castle are two that i personally use) and get some good genetics.
When using CO2 - the temperature is tied to the amount of CO2 in the air. If you can get the plant to take 2,000PPMs - you can run your temps up into the mid 90s. If you are at 1500PPMs, then you can run them around 85. Anything above 2,000 and 95 degrees will likely hurt your plant - and I would claim that you need to be an expert grower to do this. There are going to be people coming in and commenting that you can't do this and that you must run the plants at 75 - no matter the CO2 level. But plant metabolism is tied to heat, the more heat, the faster the plant produces. Extra CO2 allows the plant to have an elevated metabolism and actually use the heat.
I will state up front that I disagree with the "it must be 75" crowd - and that my information comes from personal experience and a book entitled "The Cannabis Grow Bible" by Greg Green.
And... there are tropical strains that can and do grow in temps all the way up into the low 100s. In this same book, the claim is made that some varieties can handle temps as high as 120. But none were mentioned by name.
The other tip that will help is Silicon. Very few of the nutrient mixes include Silicon. Soil contains nearly 30% silicon. If you are doing a hydro or soilless medium type of grow - you should use Si as an amendment. Silicon does two things - it makes the plant tissue less brittle and it allows it to handle higher temperatures without stress.
One of a combination of these tips should help.
Would all those seeds be female if pollinated by a female?
Thanks
No, not necessarily. Genetics is a game of happenstance and statistics.
There are several good strains that have been developed from feminized lines by finding a male out of thousands of feminized seeds and then using this in the breeding program.
