Nyack Community Garden
Diseased tomato leaves from our garden
A tomato disease hit our garden hard starting in the damp month of August. You’d hear talk of “blight” if you conversed with other gardeners but is it really the same disease that killed our tomatoes in July of 2009? That disease struck farms and gardens throughout New York and was Phytophthora infestans, or late blight, the same fungus that was responsible for the Irish potato famine. This disease is clearly not the same. For one it does not affect the fruit, whereas blight does. In addition its lesions have a different shape and color from late blight symptons (see tomato blight for pictures). Finally farmers and gardeners and scientists are not talking about blight this year in New York, it’s next to impossible that there would be a late blight infestation around that’s only affecting our garden given how devastating the blight was to all the local farms in 2009.
I’ve looked at various Web sites and concluded that it’s likely to be Stemphylium, or the gray leaf spot fungus. I’m thinking this because of the affected tissues, leaves only (not stems or fruit), and the appearance of the lesions. Take a look at the pictures, these show how the disease progresses:
This link talks about the disease and how to manage it: gray leaf spot
Here’s some common-sense advice:
Posted by Brian O. on Oct 03, 2011
Best Vegetable
Best Flower and Vegetable
Best Maintained
Best Overall
Judges
Well done!
Continue Reading…Posted by Brian O. on Aug 07, 2011
On June 1 at 7:30 there will be a presentation by the Cornell Cooperative Extension entitled "Overview of gardening practices and Q&A from gardeners". At the Nyack Senior Center, 90 Depew Street.
Continue Reading…Posted by Brian O. on May 23, 2011
On August 10 at 6:30 the Cornell Cooperative Extension will do a class on "Planting a Fall Crop" at the garden.
Continue Reading…Posted by Brian O. on May 20, 2011
The second test performed by Cornell Nutrient Analysis Lab was their #1030 Soil Fertility Test. The results, above, are expressed in mg/Kg, equivalent to parts per million (ppm). The table below shows recommended ranges for some of these nutrients in farm or garden soil.
The previous article on soil tests mentioned some high total, metal levels, like those for iron (Fe) and aluminum (Al). But these metals only harm your plants if the soil is acid, which will dissolve the metals and make them available to the plants. You can see at the top that the soil’s pH is 7.04, nearly neutral, neither acid nor alkaline. So we’re in good shape there, the plants will do fine with the Fe and Al levels in our soil since most of the iron and aluminum is insoluble.
On the right you can see that the phosphorus (P) and potassium (K) levels in the soil are high, a bit above the optimum, in fact. This means that you do not need to fertilize in any way that will add P in particular, we’ve got enough already.
We also have plenty of the trace, soluble, minerals magnesium (Mg), calcium (Ca), iron (Fe), aluminum (Al), and zinc (Zn). The only mineral that’s on the low side is manganese (Mn) but even then it seems that you’d only try to add manganese to your soil if it’s less than 20 ppm and we have about 32. Remember that all living things need these minerals, they just don’t want too much of them.
Then we come to loss on ignition (LOI) and organic matter (OM). The levels are very good, around 10%, well above what some would consider the minimum amount of organic matter, which is 2%. Mind you though, this soil is taken from a plot that gets covered with hay every year. I even take my weeds (and my neighbors’ weeds!) and layer them underneath the hay where they decompose quickly. There’s a name for this, it’s called strip mulching. Between the hay and the weeds I’m adding a lot of organic matter to this soil, your plot probably is different if you’re not adding organic matter to it.
Finally we get the soil nitrate level (NO3), about 14 ppm. One way agronomists talk about soil nitrate is to refer to specific plants and their nitrate requirements. For example, if you grow sweet corn you want plenty of nitrogen, at least 25 ppm of nitrate. So to grow the best possible corn you’d find a way to add nitrogen to your plot, by adding manure or blood meal, or by growing a cover crop and tilling it in. Tomatoes, peppers, and squash are similar in their nitrate needs, ideally they get nitrate in the range of 25 to 50 ppm. Of course these plants grow and make great vegetables with less than 25 ppm nitrate but if you want the best possible outcome you’d add nitrogen in some form.
If you do add some form of nitrogen follow the instructions carefully! Over-fertilizing with N will give you big plants with lots of foliage and not much else. Great for cabbage, not so good for tomatoes.
Here’s a nice PDF on soil testing, if you’re interested in reading more: Understanding the Numbers in Your Soil Test Report.
Continue Reading…Posted by Brian O. on Apr 11, 2011