From now until mid-October is the best time of year for planting most trees and shrubs and overseeding lawns.
Planting now will give woody plants two cool seasons, fall and spring, to establish their roots before it gets hot next summer. A major problem may be finding some of the plants that you want since selection is a bit more limited this time of the year.
It also is time to repair or thicken a weak lawn by mowing the grass short, dethatching the lawn and seeding. Don’t use inexpensive seed. You usually get what you pay for in seed. If you have a fescue lawn, stay away from Kentucky or K31 tall fescue unless you already have K31. Although it is a very good grass, it is coarse textured and is best suited for your yard if you have cows.
Q: I have several pear trees in my backyard that are loaded with fruit. Can you tell me when they will be mature or how I can tell when they should be picked?
A: Pears will have a slight color change to the skin when they need to be harvested. This color change may be difficult to see if you are not paying attention because it is subtle. They will go from green to light green but not yellow. Start checking them now.
Hood, an early pear, has already been harvested.
Bartlett pears should not be left on the tree to ripen or their flesh will be grainy instead of buttery in texture. Their flavor will be fine but the texture will not be what you might like. A surefire way to know when they are ready is to cut open a fruit after you see this color change. The seeds should be nearly all brown when harvested.
Allow them to finish ripening at room temperature in the open air for a few days and their flesh will be a good texture.
Q: Recently, you answered a question about when to water cactus: “every two weeks or a month depending on how much you want the cactus to grow.” What I would like to know is that when you do water, how much water do you give the plants? A quart? A gallon?
A: Too much water really refers to frequency, not amount. Watering too often usually results in plant death. Too much water applied at one time usually results in water waste.
The amount of water applied depends upon the size of the plant and how it is managed. Larger-growing cacti need to have more water applied than smaller cacti. Tall cacti need more water applied infrequently to help their roots grow deep and keep the plant from falling over.
Without knowing the size of the plant it is impossible to tell how much to give it. I think it is more important not to water too often.
Q: I have a few questions about a previous lawn overseeding answer you gave. Unlike the person asking the question, my summer grass is OK. My lawn has not been overseeded for winter. I assume that the advice about overseeding with fescues only relates to a summer lawn. I have Bermuda grass. In my case, I assume I should overseed with Palmer or Prelude ryegrass in the fall for a winter lawn.
Also, what is a power rake? Does that mean just vigorously rake to disturb the top of the lawn? What temperature (or time) in fall is ideal for overseeding with winter rye? How should I coordinate fertilizing with the planting? When do I need to aerate the lawn?
A: All cool-season grasses like fescues and ryegrasses have to be seeded during cool weather or they will not germinate easily. Overseeding Bermuda grass with perennial ryegrasses, like Palmer and Prelude, also has to be done during late September and October. Other ryegrasses will work as well. Perennial ryegrass will give you better winter color than annual ryegrass.
Bermuda grass loves the heat and becomes dormant (turns brown) in winter. Fescues and ryes like cooler weather and can handle the cold winter better. September and early October is when Bermuda grass is going dormant while fescues and ryes will do their best. The idea is to seed cool-season grasses this time of the year while Bermuda grass is preparing for winter.
To get these cool-season grasses to germinate in existing Bermuda grass, you have to open the grass up. This is done by power raking, which also is called dethatching.
For a successful overseeding, you need to understand two major concepts. The first is to reduce competition from the Bermuda grass and prepare a seedbed for the ryegrass. Competition is reduced by mowing Bermuda grass short and power raking. Power raking also prepares the seedbed for the rye.
Power raking can be done manually with a dethatching rake, if one is available. You can try using a garden rake but it can be quite damaging to the lawn if you overdo it. Power raking in any form damages the lawn since it removes living grass plant parts by ripping them out.
The lawn needs time to recover from this type of damage, but this damage does open up the lawn for better seed germination. Of course, when you do this the lawn also is opened up to weed-seed germination. There are many more weed seeds to worry about that germinate in the spring rather than the fall so we try to avoid power raking in the spring.
Most equipment rental places have gasoline-powered power rakes for rent. They also may be called dethatchers or vertical mowers.
The second concept is that good germination of seed requires good soil-to-seed contact. The seed must rest on the soil surface, not on top of a bunch of dead grass lying on top of the soil.
Power raking or dethatching removes this layer of dead grass, called thatch, and improves seed germination. When you are done power raking you should see bare soil.
Aeration really has little to do with overseeding. Aeration, or punching holes into the ground, doesn’t disturb the grass very much so it can be done any time of the year. But, it really is best done at least a month before hot weather arrives. Aerating is normally done with a machine that you can rent.
Aeration helps water and air move into the soil and allows for deeper rooting of turfgrass. As water and air are allowed to move deeper, plant roots will follow. Deeper roots mean better resistance to drought or dry conditions.
To stimulate the rooting of grass, I like to suggest an application of a high-phosphorus fertilizer right after aeration. Phosphorus stimulates root growth.
If your lawn needs some nitrogen, too, then apply a fertilizer with a rating something like 16-20-0. If the lawn is a nice deep green color and does not need more nitrogen, then just apply something like triple super phosphate or 0-46-0 and avoid excessively fertilizing your lawn with nitrogen. Excessive nitrogen can weaken lawns.
Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at firstname.lastname@example.org.