46 June 11, 2008

We have had our first heat wave of the season. At least this year, we had some spring weather before the hot days arrived.


Hot and humid weather can have an effect on your plants. When the temperatures are above 90 degrees, tomato flowers do not “set”. The bees may pollinate the flowers, but the flower pollen just doesn’t “work” If you have tomato flowers that are open during hot weather, you can spray the flowers with a product called blossom set. This comes in a trigger spray bottle. All you need to do is to spray the clusters of tomato flowers with this product and the flowers will “set”.  You can also use this product on squash.


Hot weather also puts a tremendous demand on your plants for water. Plants take up water better in the early morning. You should be watering your plants in the morning to allow your plants to take up the water that is needed to get through the heat of the day.


Heat waves also bring humidity. Personally, I would much rather have cold weather than humid weather. Your plants, on the other hand, tend to grow better in the humid weather. There is only one problem. Well, maybe two. Humid air allows moisture to condense on the leaves of your plants during the cooling nighttime hours. This moisture on the leaves is an invitation for fungus diseases to grow on the leaves of your plants. Rose bushes, many perennials, and many of your vegetable plants are susceptible to fungus diseases. You can spray your plants with fungicides to prevent diseases or to stop active fungus diseases. There is also an organic approach to controlling fungus diseases. You can spray your plants with a product called Serenade. Serenade causes the natural defenses of the plants to become active, allowing the plant to fight off the disease. In the past few years, I have had good reports back from customers who have used Serenade.


Humid and hot weather will also make your plants grow faster. This will mean that the plants will need more fertilizer to keep up with the growth of the plants. Any plant that is grown in a container will use up the fertilizer that is in the soil. Container grow plants can take the existing fertilizer that is in the soil in about 1 weeks time. This is especially true if you are using water-soluble fertilizers. Many of the national brands have changed their formulas in the past 2 years. Instead of the fertilizer being high in phosphorous, the product is now high in nitrogen. If you are using a water-soluble fertilizer, use a fertilizer with a 20-20-20 formula. This is a balanced fertilizer that will allow your container grown plants to grow their best.


An exception to this rule is fertilizing the new varieties of hanging petunias.  These plants need higher amounts of iron and a larger amount of nitrogen. There are fertilizers that are formulated for these new petunias. If you have these new varieties in your hanging baskets or window boxes, you should be using this new formulation.


Well, that’s all for this week. I’ll talk to you again next week.

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