Frequently Asked Questions: Fall 2010

Question
Help, I'm confused. Does my lawn need to be feed with a "winterizer" lawn food later this fall and how late can it be put down? I don't know what to use. Can you help clear up the confusion and advise me on what kind of lawn fertilizer is appropriate for Colorado? Are organic lawn foods OK in the fall? Do lawns need to be fed with an iron supplement here?

Answer:
Grass plants don't read the fertilizer label and as turf specialist Dr. Jack Butler once stated, "the term winterizer is a misnomer and if you're applying a lawn food, put it on before the beginning of winter." Lawns need a proper balance of nutrients in the fall to help build up carbohydrate reserves to endure the winter. For cool-season lawns in the Rocky Mountain region, use a fertilizer with nitrogen (the first number on the analysis) up to 20 percent and with less phosphorus and potassium. Some examples would be formulas such as 20-10-5, 21-7-11, 18-6-12, 14-2-4 and 11-5-5. Organic-based fertilizers generally have a lower nitrogen level, but they can also be utilized now and are especially effective when applied after the lawn has been core-aerated. The organic components of the fertilizer will filter down into the soil and help condition hard, compacted soils. Lack of available iron, termed iron chlorosis, is often the cause for the light yellow color of lawns. This is typical of our region. Fertilizers manufactured in our area will contain iron and sulfur, whereas most national brands contain little or no iron. Read the label closely before purchasing so-termed "winterizer" lawn food.

Question
I had a problem with my tomatoes this year. Many of them ripened but they had big splits and cracking throughout the outer skin. What causes this?

Answer:
The primary cause of cracking is due to certain weather conditions, primarily dry, hot weather in mid-summer followed by too much water when the fruits are maturing and ripening. To reduce this problem in the future, spread organic mulch around the base of plants to maintain uniform moisture conditions and help keep the soil from baking during the summer heat. There is no cure for splitting fruits and some varieties are much more susceptible than others to these growth cracks.

Question
I have been told to clean up dead plants in the fall. Is this really necessary or can they be left in the ground until spring?

Answer:
It depends upon this year's gardening season and the general health of the plants in your landscape. If your garden was plagued with diseases and insect pests, I would advise that you do a general clean-up during the fall. This serves as sanitation to remove fungus spores and virus diseases, as well as many insects and their eggs, which will overwinter in dead leaves and plant refuse. Don't use diseased plants, leaves or weeds in compost piles. Composting methods in our region generally do not get hot enough to kill disease spores, insect eggs or weed seeds.

Question
We planted sweet corn and we're disappointed since the ears didn't fill up with kernels completely. What did we do wrong? Should the plants be fertilized more?

Answer:
Poor pollination is the primary reason for sparse kernel development on corn ears. Corn is best planted in blocks of 3 to 5 rows instead of a few single rows. This arrangement in a home garden will allow for more pollen to fall onto the corn silks. The hot, dry winds or prolonged periods of rain or overhead sprinkling can also prevent pollen from reaching the silks and pollinating the plants. Lack of proper irrigation will keep the kernels from developing into juicy morsels and filling out adequately.

Question
I live in an older part of the city and have a tough time getting the lawn to grow under a large elm tree. Do you have any suggestions that will make the lawn grow thicker?

Answer:
As trees mature the original grass varieties will not thrive as well when there was more sunlight reaching the ground. Lawn grasses are more susceptible to lawn diseases including powdery mildew, which causes the lawn to thin out. Grass will have to compete with surface-roots of the tree for water and nutrients. There are some excellent shade-tolerant bluegrass varieties that can be over seeded in the shady areas. Look for Bristol, Eclipse, Enmundi, Mystic, A-34 and Nugget at a seed supplier. Aerate the area thoroughly to provide openings for the seed to lodge and it will germinate and establish vigorously. Water and fertilize adequately to lessen the competition from the large tree.

Question
The leaves on my purple leaf plum shrub looked terrible this summer. They turned brown and look wrinkled. You can even see through the leaves in some places. What's going on with my plum?

Answer:
The culprits that caused this damage are already gone by this time. They are pear or cherry slugs, which are not related to the familiar garden slug. These pests are sawfly larvae and as they feed they skeletonize the leaves, thus giving them a transparent look. Next year, watch for yellowish-green, slimy slug-like crawlers on the foliage. As soon as they appear, hose the leaves down with a forceful spray of water and this will reduce the leaf damage. Insecticidal soap sprays and contact insecticides will also give control but follow label directions carefully to prevent spotting of the leaves.

Question: July 2010

I have two dogs and a cat and don’t want to use bug killers in my garden. What are some good alternatives to get rid of the insect pests that invade my flowers and vegetables?

Answer:

I applaud your quest to avoid toxic chemicals for pest control. It has been reported that there has been an increasing rise in the misuse of over-the-counter pesticides in the home garden. Hosing down wimpy pests such as soft-bodied aphids with a strong stream of water from the garden hose will keep an aphid infestation at bay. Hand-picking cucumber beetles, squash bugs, bean beetles and caterpillars and dropping them in a pail of soapy water will eliminate these pests. Whiteflies in garden can be trapped on pieces of poster board smeared with sticky glue. Hang the coated traps among plants that are often attacked. If homemade sprays are not strong enough or you have an overwhelming pest problem, the next step is to try an “organic pesticide”. Read the labels carefully and follow them exactly. Horticultural oils, insecticidal soap formulations, and botanical insecticides are generally safe to use on most garden plants and edibles. Organic pesticides break down more quickly and have a milder affect on the environment. They, too, should be used as a last resort. The over-the-counter organic pesticides are not only toxic to insects and diseases you’re trying to eradicate, they can also kill honeybees, various beneficial insects, soil microorganisms, birds and other wildlife that are part of the garden ecosystem.

Question: June 2010

I have a peony plant that is several years old and it has healthy foliage. In past years it produced many large blooms. However, this year it had few flowers and they were small at that. What causes this?

Answer:

It is very likely that your peony is not getting enough sunlight; they need a minimum of six hours or better yet, full sun. If your landscape has maturing trees that cast shade over the plant, this can contribute to a weaker plant and less flowering. Additionally, if the plant suffered from drought stress last fall and winter, this can weaken the plant and it will form fewer flower buds.

Question:

Why do my daylilies grow with very healthy, green foliage but they don’t produce many blooms?

Answer:

Daylilies need to be growing in at least six hours or more of sunlight for the good flower development. If shrubs or trees in your landscape are maturing and casting shade on the daylilies this may be one of the causes. Be sure you are not over-fertilizing with fast-release, high nitrogen plant food as this will result in more foliage and few blooms. Use an organic-based fertilizer with a higher middle number. I prefer the Gro-Rich Rose & Perennial Food which is slow-release and helps condition the soil as it feeds.

Question:

My flower garden is being invaded by pincher bugs. They chew chunks out of the leaves and flowers. How can I get rid of them without the use of a bug killer?

Answer:

Sounds like the European earwig that commonly feeds on flowers and other tender vegetation. Earwigs hide during the day in dark places and come out at night to feed. They are considered beneficial insects as they also feed on other harmful insects and spider mites. As their population increases in the summer, earwigs can cause considerable damage in the garden.

My favorite method of control is to trap them in rolled up, dampened newspapers. Place the rolls throughout the flower beds at dusk and the earwigs will migrate to them in the wee hours of the morning. Collect the newspaper rolls in the morning and they should be teaming with the critters. Dispose of the pests by shaking into a bucket of soapy water or if you’re not squeamish, do “the earwig stomp”.

Heavy accumulations of organic mulch can encourage more earwigs, so you may want to reduce mulch thickness. Also, allow mulches to dry out periodically between watering to discourage earwigs.

Question: May 2010

What kinds of tomato varieties do you recommend for this area? (Colorado/Rocky Mountain Region)

Answer:

If you are new to growing tomatoes in this region, it is important to know the climatic limitations. Generally, we have a short growing season that will not allow many varieties to mature and ripen on the vine, unless you help to extend the season. The low humidity, extreme hot days, and cool nights can prevent complete pollination of the flowers in some varieties.

I’ve had both successes and disappointments with tomatoes; it all depends on the year. Some of my favorites, that have always been dependable include: Early Girl, Jet Star, Fantastic, Ramapo, and the cherry types like Sweet 100.

Read the transplant labels for information on days to harvest and choose accordingly for your growing season (80 days of less for shorter growing seasons).

In mountain communities you can grow tomatoes in hot frames, greenhouses, solariums and other modified gardens.

Question: April 2010

A Notorious Weed Pest Question: My yard is being invaded by “goatheads” or puncture vines. These are really bad on bicycle tires and walking barefoot. Is there anything that can be done to get them under control? The more I spray or dig, they just seem to multiply.

Answer:

Puncture vine is a notorious weed that grows each year from overwintering seeds. Once the seeds come to the right level in the soil and temperatures warm, the seeds germinate. It is best to dig, hoe, or lightly cultivate areas where the young plants emerge. This will uproot the tiny plants and expose the roots to sunlight and desiccation. Chemical controls are variable in killing this weed pest, so I prefer cultural controls. Be persistent and you will eventually win the battle.

Question:

 I’m looking for an alternative to toxic weed killers on my lawn since we have kids, two cats and a dog that play on the lawn. Are you familiar with a product that is made from corn that is supposed to prevent the growth of weed seeds? Is it available locally?

Answer:

 The material to which you refer is a natural pre-emergent weed control made of corn gluten, a by-product of corn syrup production. Children and pets can play on the lawn right after application. Research has shown that corn gluten will provide up to 90% pre-emergence control of lawn weeds including dandelions, purslane, spurge, crabgrass, creeping bentgrass, foxtail, clover and other weeds. The active ingredients work by inhibiting the development of feeder roots. Weed seedlings will quickly die, usually within the first few days after seed germination. Whereas chemical herbicides pose a threat to trees and shrubs, corn gluten will not leave any toxic residue in the growing zone of tree and shrub roots.

 Corn gluten pre-emergent weed control is available locally at the Wild Bird Center in Denver at South Colorado Blvd. and Mexico; 303-758-7575, and the Wild Bird Center in Parker at Stroh Ranch and Parker Road; 303-805-5982.