I don't know about the rest of you, but I am glad it started to dry out a little.
I have some plants that needed to be put out, but this wet weather has everything delayed. Everything except the rate at which those plants are growing. I have yet to try to grow a cabbage indoors, but if the weather doesn't straighten out soon, I might be doing just that.
This wet weather could also affect the nitrogen in your garden. An article based on a survey by the University of Missouri soil test laboratory revealed a trend that most soil tested from vegetable gardens showed that soil phosphorus and potassium are becoming very high, and soil pHs are also on the rise.
The reason for the elevated phosphorus and potassium is most likely because vegetable gardeners have the tendency to seasonally or annually apply "balanced fertilizers," those that have nitrogen, phosphorus and potassium. While the nitrogen is leached by water or can evaporate or disperse in vapor into the atmosphere, phosphorus and potassium adhere to the soil tightly, thus they "build up." Use of organic fertilizers like manure or compost won't change a build up from occurring, as most organic fertilizers are balanced as well.
If your garden does not seem to be growing as well as in the past, have your soil tested and then focus on only supplying the needed nutrients prescribed by the test. Increasing organic matter, if less than 5 percent, will also help. For established vegetable gardens where nutrients have built up, the focus may be on just one nutrient, nitrogen.
Synthetic fertilizers that are slow or time release are desired by many gardeners, as they are less likely to "burn" plant tissue (either roots or foliage). Some specialty turf products are now available with only nitrogen. However, balanced formulations are more common. An option is to select slow or time release fertilizers that are highest for nitrogen and lowest in phosphorus and potassium. Often, these fertilizers are marketed for turf applications but can work well in garden also. Formulas in the range of 22-5-6 and 25-2-5 are available and will work.
There are several organic options. First, when you have the time, grow a legume cover crop and till it under about a week or two before planting. Of course this takes quite a bit of planning and it might be good to plan this for next year's garden. Legumes fix nitrogen with the root nodules and it is accumulated in the green growth, which when plowed down is sometimes referred to as "green manure" and is a good source of nitrogen. Good sources of nitrogen organic fertilizers without phosphorus or potassium are corn gluten (9-0-0), blood meal (13-0-0) and feather meal (12-0-0). The MU Guide 6220 "Organic Gardening Techniques" is a good source of information on organic fertilizers frequently used by gardeners and is available online free.
Most of the time, a deficiency of nitrogen will cause the plants to lose some of their color. They will not be a dark green as usual, even having more of a pale green tint to them. If you do find the garden needing extra nutrients after the plants have started growing, side-dressing is the method to help them.
Side-dressing applies fertilizer to the soil at the side of a row of seed or plants. It can be done at planting or as an extra application later in the growing season to help provide a uniform supply of nutrients throughout the season. This is especially important if you are using chemical fertilizers because of their solubility and their tendency to "leach" down in to the soil beyond the root zone before the growing season is over.
The usual rate for a side-dressing in the garden is five tablespoons per 10 feet of row of a high nitrogen fertilizer such as discussed above. Place about a 6-inch band of fertilizer on each side of the row, rake it in then water. A combination of chemical fertilizer, organic fertilizer and mulch works well also. The chemical fertilizers give the initial boost required by young plants, organic fertilizers provide nutrients uniformly throughout the season, and mulch keeps the soil more evenly moist and the nutrients more uniformly available.
Peter Sutter is a lifelong gardening enthusiast and a participant in the MU Extension's Callaway County Master Gardener program. Gardening questions can be sent to [email protected].