Choose fertilizer to encourage roots, stems
Did you see that harvest moon a couple of weeks ago? The moon coming over the Sandias is one of the things that makes Albuquerque so special.
Fall is my favorite season. It was in the fall of ’98 that I was on my way to Creston, British Columbia, on assignment from Sunset Magazine to do a story on the amazing cherries they grow there (they ripen in late August). Ann was with me and we were spending the night in Bonner’s Ferry. There was a glorious harvest moon and we’d gone for a walk. I stopped and took her in my arms. I told her how much I loved her and how much I wanted her with me forever. It was the best thing I’ve ever done!
As the days turn cool and there’s a chill in the night air, deciduous plants go into senescence, which is that time between summer and fall when their metabolism slows but fall color isn’t quite there yet.
So if some of your plants start looking kinda shabby and tired, well, they are! So don’t panic and start spraying, fertilizing and cultivating, just let the old folks be. On the other hand, senescence is a great time to prune because there’s still enough sap moving around to seal cuts quickly.
Even though the tops go dormant in winter, the roots of most plants don’t, and it is with this in mind that we select what nutrients to provide.
The fertilizers that should be applied in fall should focus on encouraging root development, strong stems and vigorous buds. The main element used to accomplish this is potassium (K) which is the third number in the N-P-K ratio found on all fertilizers.
The first is nitrogen and the second is phosphorous. Too much nitrogen can stimulate a lot of soft new growth that will freeze leaving dead tissue that can be a pathway for disease. Phosphorous helps set good buds that will produce lots of flowers in spring. It is particularly important for plants that set buds in fall like azaleas, rhododendrons, magnolias and viburnams (snowballs etc.).
For plants on which flower production is unimportant, such as grass, evergreen trees, and trees like oaks, ashes and maples, a small amount of phosphorous is helpful, but potassium is what stimulates root growth and makes strong stems that will overwinter well.
In snowy areas a lot of lush new grass becomes subject to snow mold and will look awful come spring. On the other hand, grass with strong stems and deep roots is ready to take off when things warm up.
That said, however, now is an ideal time to start a new lawn because it’s easier to keep the seed damp until it germinates and the new grass can be kept damp more easily encouraging it to grow and spread. The new seedlings will need plenty of nitrogen to get going, as well as plenty of phosphorous and potassium. You can find lawn starter fertilizers with an 18-246 formula or similar. I’d like to see more potassium in these.
For most plants and trees try to find a fertilizer with around 10 percent nitrogen, 6 percent phosphorous, and 10 percent potassium. I don’t know of any such fertilizer, but these are guidelines.
Osmocote Plus, Outdoor & Indoor 15-9-12 six-month formula will work very well because it releases the nitrogen slowly enough that it won’t cause a problem. Another advantage of the Osmocote is that it contains all the trace minerals, often called “minors,” that are needed together with 6 percent sulfur to help control alkalinity. Unfortunately, it’s expensive, but it is available almost anywhere.
Now is a great time to work a generous helping of sulfur into the ground around acidloving plants like oaks, maples, magnolias, rhododendrons and azaleas. Get the granular kind like what they carry at Alameda Greenhouse.
If you have an area with a lot of bulbs, the best thing to do now is work in some bone meal around them and stay away from anything else except a tiny bit of the Osmocote.
Here’s hoping for a safe Balloon Fiesta!
Dick Rifkind is a certified nursery professional. He welcomes comments and questions at miskamarie@msn.com. Please put “garden column” in subject line. For past columns, search at abqjournal. com/living.