You might think that a “garden expert” like me never experiences garden disasters or mistakes. Well, I do. Here are a few my learning opportunities for this year.
I planted two large plastic pots with dark purple and lavender veined Easy Wave petunias, chartreuse sweet potatoes, green variegated sweet potatoes and “Wasabi,” a new lime green heat-tolerant coleus. They were looking awesome until the hot weather. I was puzzled when the petunias in one pot started to wilt even though they were being watered regularly.
I discovered that the problem wasn’t a lack of water; it was too much water. The bottom of one of the 6-year-old pots had bowed outward, preventing water from draining. The petunias wilted because their saturated roots couldn’t function without air. Once I raised the pot up, the container was able to drain. The petunias succumbed, but luckily the other plants made it through. After planting replacement petunias, the container is looking almost as good as its companion.
Another problem has been my summer squash and cucumbers growing in two large pots. I filled the lower one-third of the pots with coconut coir fiber and the top two-thirds with a brand name potting mix. This mix contained fertilizer that was supposed to last for six months.
While the squash grew well early in the season, before long the oldest leaves started turning yellow. They then turned brown and died. I checked to make sure it wasn’t a drainage, watering or squash bug problem. Because the plants were still growing and putting on new green leaves, I wondered if the problem might be a nitrogen deficiency. However, the potting mix was supposed to have enough nitrogen for six months. The estimated timing of a slow-release fertilizer depends on temperature and watering practices. Knowing this, I applied nitrogen fertilizer. The new growth on my squash plants has rebounded and is looking healthy and green.
Another disappointment has been my tomatoes. I planted six tomatoes in my garden and one in a container. The one in the container is called “Beaver Lodge,” an early tomato that’s supposed to set fruit during cooler weather. It did set lots of fruit that have finally ripened. However, my other vines have been slow.
Tomatoes are a little like Goldilocks: the temperature for setting fruit has to be just right. They set fruit best when nighttime temperatures are between 55 and 75 degrees and daytime temperatures are between 70 and 90 degrees. The reason so many area gardeners like me are frustrated by a lack of tomatoes is that the temperatures have been too cool or too hot for blossoms to set fruit. The result is tomato blossoms dropping off without forming fruit.
-- Marianne C. Ophardt is a horticulturist for Washington State University Benton County Extension.