Mildew

Mildew Strikes Back!

This past Saturday, the mildew had spread across the patch of summer squash.  While *we* had been careful to avoid watering late evening, to avoid water sitting on leaves not drying off, Mother Nature had no such qualms.  For a week she rained on and off as she pleased, day and night, throwing in a few thundershowers for good measure.  Plus with the high humidity, and therefore a high dewpoint, we surely had leaves soaked in dew every night.

Nevertheless, we benefited significantly from using potassium bicarbonate (couple teaspoons mixed in a few quarts of water -- we didn't add soybean oil because that gummed up the sprayer) to prevent mildew.  Indeed, the cucumber leaves were still free of mildew, and we've had a much more abundant crop of cucumbers this year than last.  The winter squash along the fence showed some mildew encroachment, which by today according to our Thursday waterer had spread entirely over that patch.  Interestingly, the winter squash under the beans and corn was still free of mildew. Perhaps yet another advantage of growing the Three Sisters together!

 

 

Mildew follow-up

There is no sign of mildew in our Garden.  We try to have people water in the morning if possible, as there's more water lost to heat and evaporation mid-day, and water in the evening can linger on the leaves overnight, which can result in mildew.

I checked the sunflower leaves, which last week were getting eaten badly.  They looked about the same to me, and new leaves had little munching upon.  So maybe applying potassium bicarbonate did give the leaves enough of a different taste to whatever was eating them.  Or maybe they just moved on for other reasons.  Or maybe the planted adapted by changing it's own chemistry.  So many possibilities; it's hard to know what works.

Unfortunately, I didn't make arrangements with the person who has the sprayer, and he was on vacation today, so I didn't apply any potassium bicarbonate today.

About: 

Fall Crop Update

The peak of the harvest is past, and yet we tried second plantings of some crops because we had the space, to see what would happen.  With about a month to go, here's their progress.

Cabbage & Cauliflower:  large leaves, producing well, but no sign of heads yet.

Carrots:  leafy fronds are doing well; no sign of poking out of the ground.

Beets:  alive but struggling.

Spinach:  mostly eaten by Something.

Peas:  half-height, base leaves yellowing, no sign of peas.

Lettuce:  looking good!  Might harvest some next week.

Also, here's an update on some first plantings:

Eggplant:  *continues* to produce, though more slowly.

Beans:  the bush beans produced another handful; the pole beans have disappointed.

Potatoes:  we pulled a single plant to obtain some potatoes for display at Town Day.  The number amidst the roots was extensive, and while mostly small-to-tiny, there was at least one big red one.  From just one plant!

Squash:  the tiny zucchini was accidently harvested; there's still a medium yellow squash; and the pattipan has several small fruits (not to mention flowers) which it thinks it has time to make bigger -- we'll see.

The mildew is back to some extent on the squash, and worse, has jumped to the other side of the garden and covered the collard leaves.

The rest of the greens (kale, chard, arugula and other herbs) still doing well.

Pesticides vs. Mildew

Mildew attacked the leaves of cucumber plants and zucchini (and other summer squash) plants this summer.  Despite this, we harvested abundant quantities of each, so one could just call this part of our ecological tithe, especially since we weren't eating the leaves.  Yet there was enough concern that we did try to address the problem.

We altered our watering, so as not to water from above near these plants (as well as the tomatoes, given the threat of tomato blight).  Water on leaves helps spread disease, and it's water into roots which counts.  We added a soaker hose in the area of these plants as well.

We also tried a couple pesticides.  The first was a dilute mixture of hydrogen peroxide.  The effectiveness was questionable, requiring multiple regular applications to seem to work.  The second was baking soda and soybean oil (vegetable oil) diluted in water:  about a tablespoon of baking soda with a half gallon of water; the oil helps the baking soda stick to the leaves.  A few days later, many of the leaves of the squash plants appeared free of mildew.  However, it is unclear how much of this is new growth unyet touched by mildew, since we cleared away the dead leaves.

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