Wednesday, August 8, 2007

Squash Problems in Harlem

Here is a picture of the mysterious disease on our squash plants. One whole bed of squash has perished - the spots have moved on to a (nonadjacent) bed of zucchini - I fear for their safety. Can you please tell me what you think is going on here?Question:

Here's another picture if you can help figure it out. Some of our cucumbers are growing weird and lumpy... might just be random but if you have any ideas I'd love to hear them!

As far as the squash, I think the situation is a fungal disease called powdery mildew. It occurs when there is not adequate air circulation to the garden, and it happens a lot throughout NYC. When there is not a lot of fresh air flow in the area and then lots of watering the leaves and stems can get covered with this white film. When the leaves are covered enough the plant cannot photosynthesize and the leaves die. In the extreme cases, if all the foliage gets affected then the entire plant can die as a result. There is a homemade remedy that people swear by. What you do is mix into a gallon of water two tablespoons of baking soda and a little dish soap (Dawn, Palmolive, etc.), just a drop to make the mix more viscous. Use this mix as a foliar spray and try and cover as much of the affected leaves as possible. Do this early in the morning when it is cooler and before the hot midday sun is out. If there are leaves that are really bad, just go ahead and prune and remove them to the garbage. In addition, try and increase the air flow as much as you can, removing any weeds or leaf debris that might be at the base of the plants.

As far as the misshapen squash, I am less sure as to why they are coming out looking so funny. It could have to do with the amount of water and/or the watering schedule you have the plants on. I suppose if you water heavily and then the plants go dry between watering then you can end up with some “lumpy” veggies. In addition, the rain storms we have had this summer have delivered so much water in such short periods of time, those mixed with hot dry periods in between might bring about some oddly shaped vegetables. If you water your plants with the same quantity of water and the same regularity throughout the week then you may end up with more “normal” looking vegetables. But I am sure even though they may look a little funny they are still perfectly healthy and worthy of being eaten. Think about how “perfect” the vegetables in a supermarket look – that is because farmers have their crops on a set schedule getting watered the right amount every day. For you and I who grow veggies in our own gardens they take on different shapes – that is most likely because the amount of water and how often we water can vary more. Another thought is that if the plants are battling with powdery mildew that may be affecting how efficiently the plants produce squash. My final thought has to with the presence, or lack thereof, of pollinators. According to Rodale's Garden Answers here in our library, misshapen fruit may be due to poor pollination during hot weather. There has been much talk about bee populations suffering in NYC and this may be a visible sign of that. If you do not see many bees in your garden then there is actually a way of pollinating your crops by hand and I can easily pass that information along to you.

For both of these questions I should say that there is a mosaic virus that can affect squash foliage and fruit, but none of the symptoms you have describes sound like this extreme of a problem.

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