On 2004-06-15 03:41:27 -0700, dps said:

Dusty Davis dustydavis - at - gmail.com wrote in message
news:2004061412353170377%dustydavisatgmailcom@news .charter.net...

...I've searched for info and come across two possible causes: calcium
deficiency or too much moisture. I haven't done a soil test, so I'm not
sure about the calcium. I'm using a drip system, but I also do overhead
watering quite a bit - perhaps that is the problem? If I did supplement
the soil, is there an organic or relatively natural method?



Blossom end rot is generally attributed to calcium deficiency. That's a
deficiency in the fruit, not necessarily in the soil or even in the
plant. Calcium availability in the soil is reduced by low pH, so a soil
test might help. I've never had much luck with foliar feeding. On the
other hand, blossom end rot on squash and tomatoes appears to be more
common on early fruit, when the calcium in the plant is redirected from
the fruit to the growing point of the plant. Frequently the plant will
grow out of the problem and the later fruit will be free of blossom end
rot.

Overhead watering can be a problem with tomatoes, but I've not had a
problem with squash. The only other problem I've had with squash is
powdery mildew. I control it with an application of what is basically
hydrogen peroxide. The peroxide kills the mildew, although heavy
infestations may require several treatments. I use Oxidate (trade name)
which is 27% peroxide, diluted 100:1. The stuff in the grocery store is
generally 2.5-3% strength, so a dilution of 10:1 would be appropriate.

Striped cucumber beetles can be a problem with any cucurbit. Surround
(trade name) is a fine kaolin clay which you can mix with water and
spray on the seedlings. It helps to keep the beetles off the young
plants, which is when most of the damage is done.

I belive both these pesticides are allowed under the National Organic
Program. (Note that this doesn't make them completely safe. Hydrogen
peroxide, while used as a mouthwash, is an oxidizer and can damage
plants and animal tissues at full strength. The clay can be dusty, so
it could be an inhalation problem.)

Thanks for the info! I've purchased a soil test kit and I'll test the
zucchini bed this afternoon. I should have done it before planting, but
live and learn... I'm hoping the later fruit will not have the same
problem.

I haven't had the other problems you mentioned (mildew or beetles) to
this point. The plants have been incredibly fast-growing and strong,
and until the blossom end rot, free of trouble.