Q. I have a large clump of day lilies that have outgrown its spot. When can I dig up, divide and transplant them to a new area in my garden?
A. Clumps should be dug in the late summer, immediately after flowering, or early fall, at least six weeks before the first hard frost (Oct. 1-15 for our area). Dig up the entire clump, carefully avoiding damage to the tuberous roots. Remove as much soil from the clump as you can and divide the individual plants, called fans, by just pulling them apart. If they should resist, a sharp knife can be used to carefully cut them apart. Each fan can be planted individually to the same depth as they were previously growing. Plant them about 18 to 36 inches apart. The green leaves may be cut back to about 10 inches to a foot, or about half their original height. After replanting, keep the soil around the plant evenly moist this fall and next spring.
Q. How many growing degree day (GDD) heat units have we accumulated so far in 2015, and how does this compare with the average of 2009-15?
A. Growing degree day heat units are a good way to predict the amount of growth for a specific crop as long as it has adequate moisture and the base temperature matches the crop, which is 41 degrees for timothy hay. Since Jan. 1, the timothy hay GDD heat units accumulated for Mesa (31.5), WSU Roza Farm (38.0), WSU Othello Research Farm (33.4) and WSU Tri-Cities Campus (30.1) percentages were higher than the average from 2009-15, respectively.
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This means that we have from the beginning of year to July 7 accumulated about 33 percent greater number of heat units compared with the seven-year average. In other words, it has been hot in 2015 so far.
Q. What does NPK mean when talking about fertilizers?
A. The NPK is the nutrient analysis of the product in the container, or the percentage by weight of the product of the three major plant nutrients: (N) nitrogen, (P) phosphorus and (K) potassium. Minor plant nutrients are sometimes also included, and will be at the end with a letter to indicate which nutrient. For example 21-0-0+24 (S) is 21 percent nitrogen and 24 percent sulfur.