November 14, 2019 0 Comments

Can I Still Plant? First Frost & Fall Establishment

Most regions of the U.S., with a few exceptions, have experienced their first frost of the season by now. And landscapers are among that select group of people for whom that first dip into freezing temperatures means more than just it’s going to be a chilly day. An avid gardener, I watch that daily high and low with an eagle eye every fall and spring. On more than one occasion, I’ve had to drop everything and make it a priority to move all my pots indoors for the season. As a result, I’ve come to view that 32 degrees F with a sort of mysticism. It seems a dark magic must be at work to transform a vibrant, huge coleus one day into a wilted mess the very next. So what does first frost actually mean and does it end the planting season?

Fall Frost Forecasts
According to the National Weather Service (NOAA), hitting 32 degrees and first frost in the fall aren’t necessarily synonymous. “Frost can occur when the temperature falls below 36°F, especially in rural areas. It is a localized phenomena and can be quite variable across a small area. While the National Weather Service does not keep track of ‘frost’ in observations per se, we do keep track of when temperatures hit the freezing mark or fall below. Frost becomes more widespread when the temperature falls below 32°F with some freeze possible. A hard freeze is possible when temperatures fall below 28°F.” Here’s a breakdown of NOAA terms:

Frost Advisory: issued when temperatures, winds, and sky cover are favorable for frost development. Most likely when temperatures are less than or equal to 36 degrees. Frost coverage should be more than patchy. If a frost is sufficiently severe to end the growing season, it is commonly referred to as a ‘killing frost.’ What to do – Cover up plants before the sun sets so to help retain heat.

Freeze Warnings: issued when low temperatures are expected to be 29-32 degrees. What to do – Move sensitive plants inside.

Hard Freeze Warnings: issued when temperatures are expected to be 28 degrees or less. What to do – Sensitive plants must be moved inside because the freeze will kill them.

A color coded map from NOAA shows the average date of first freeze in regions across the U.S. A very convenient search of frost risk dates by percentage can also be found on the popular gardening site, Dave’s Garden. Simply type in your area code for information. For instance, when I typed in a NJ area code, it revealed, “Each winter, on average, your risk of frost is from October 15 through April 30. Almost certainly, however, you will receive frost from October 29 through April 17. You are almost guaranteed that you will not get frost from May 13 through October 1. Your frost-free growing season is around 168 days.” It also included charts from three NJ weather stations, provided by the National Climatic Data Center, breaking down by percentages, dates, and temperatures the probability of first freeze or last frost.

What Can Be Planted?
Of course, not all horticultural work has to cease after first frost since the soil stays warm longer than the air. Spring flowering bulbs can still be planted until the ground freezes. And while September and October are generally the best months to plant new trees and shrubs, the experts at Davey Tree say as long as the ground isn’t frozen yet, there are still some varieties that can be planted after first frost. Here is more specific advice from Davey’s arborists:

• Avoid planting evergreens after first frost. It’s difficult for them to establish roots and preserve needles with the limited water supply in winter.

• Also avoid planting birch, dogwood, willow or magnolia since they need more time to establish. Plant in spring and water throughout the summer.

• Unless your area has a mild or warm winter, hold off on planting new fruit trees until the spring so they aren’t damaged by winter weather.

• Generally, other deciduous trees and shrubs can be planted if they will have at least four to six weeks to establish roots and drink water before the soil freezes.

• Not sure about soil temps? Use a soil thermometer. If soil is consistently 50 degrees or higher, it’s safe to plant deciduous trees or shrubs.

• In areas where the ground does not freeze, late fall and winter planting can actually be ideal because trees can establish roots before hot, dry weather sets in.

*In Florida, you can most likely plant any time of year, but unlike the states listed above, the rainy season from May to October is best.

• If you do plant, make sure to mulch and water weekly until the ground freezes. Trees that have been planted for at least a year can be fertilized when dormant in late fall or early winter.

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July 20, 2019 0 Comments

Lawn problems & watering at night.

Watering your lawn at night offers the main benefit of reduced evaporation; you conserve water while maximizing your turf’s absorption ability without the sun’s constant heat. Watering at night, however, can encourage disease in a poorly managed lawn. Although healthy turf may not have obvious disease issues from nighttime watering, irrigation should occur during morning to avoid possible grass damage over time. Whether it is best to water lawn in morning or afternoon depends on the time of year.

Ideal Timing for Watering the Lawn
During spring and summer, lawns must endure afternoon heat stress because most grass species grow best in full-sunlight locations. Help your grass endure the long, afternoon sunlight by irrigating your lawn in early morning. Evaporation loss is minimal because wind and sunlight are limited at that time of day. Also, plants absorb water faster in morning than during afternoon.

The absorbed water helps grass retain its green hue and upright posture throughout the day. Watering lawn in morning or afternoon is helpful during the colder months because if a particularly cold night is ahead, daytime watering allows time for the moisture to move into the soil to protect the grass from frost damage.

Disease and Lawn Watering Schedule
Many bacterial and fungal diseases rely on wet foliage for reproduction and to spread. If you water lawn at night in summer, the lack of evaporation provides time for the pathogens to infiltrate your grass. Morning watering allows time for evaporation and soil absorption, keeping foliage dry overnight.

Overwatering any time of day, however, causes major lawn problems. For example, soggy soil reduces oxygen supplies and causes grass stress. As a result, pathogens, such as root rot, set in and damage the lawn until you correct the soggy conditions. In general, water infrequently to a 6-inch soil depth each time; watering a little bit each day only encourages shallow roots that succumb to drought stress and possibly disease.

Water Lawn Morning or Night to Prevent Pests?
Pests use nighttime to invade a lawn while unseen. As you water your lawn in morning, you have a chance to remove the pests, such as snails, to prevent widespread turf damage. As grass blades swell with moisture, they are more difficult for small pests to damage; wilting grass blades allow simple access to their internal areas upon which pests feed. Morning irrigation efforts keep grass strong for natural pest resistance, which means you don’t have to rely on spraying harmful pesticides across your yard.

Watering for Effective Turf Management
Compacted soil and a thick thatch layer of decaying stems and foliage hinder water absorption and may contribute to puddling on grass turf’s surface. Nighttime watering of a lawn with poor soil often suffocates grass roots and invites disease to the moist areas. Aerating soil by removing 1- to 2-inch long soil cores from the ground rejuvenates grass by providing better access to moisture and oxygen.

Aerated soil reduces puddling and disease while moving precious water into lower areas of soil where roots can absorb the water. Aeration also reduces the thatch layer, allowing healthy water absorption during morning irrigation.

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