Warm Air, Cool Soil

Warm air temperatures build anticipation of plant growth but keep in mind that cool soil temperatures will strongly moderate growth during the spring. Turf growth typically will be very slow until [Read more…]

Traffic Alert: Damage Threat is High

Damage to landscapes from traffic can be severe during winter and especially now during the thaw. Soil conditions currently range from being frozen to partially thawed/frozen to thawed.

Partially frozen soil will be thawed and very wet at the surface while being frozen at some depth below. Under this condition, soil and turf will be extremely vulnerable to shearing and rutting damage. Traffic, even light foot traffic, must be withheld when this condition exists otherwise severe rutting (soil displacement) will occur.

Severe rut in partially thawed soil.

Severe rut caused by a wheeled vehicle driving on partially thawed soil.

Soil temperature has been “stuck” at freezing for some time now. Today is the first time this year that I have noticed the 2-inch deep bare soil temperature was above 33 °F (> 35 °F at the time of writing this post) at the New Brunswick Rutgers Gardens weather station. Interestingly, the 2-inch soil temperature under sod at this station remains only tenths of a degree above 32 °F, illustrating the insulating effect that vegetative cover has on soil.

Keep in mind that just because a soil has thawed doesn’t mean it is out of danger from traffic. At this time of year, soil will be very loose from frost heaving and very wet or saturated. Soil on very well drained sites will firm up sooner than poorly drained sites but all sites will be very susceptible to damage from traffic for some time after a thaw. Care should be taken to avoid traffic of any kind when the soil and turf is vulnerable.

Allow soil to thaw completely and drain to at least field capacity (preferably drier) before allowing traffic on the landscape. Draining and drying will help to re-settle areas that frost heaved. Light-weight rolling may be need on soil that experienced extensive frost heaving and remains too loose after draining and drying.

Winter Thaw about to Begin

If the 10-day forecasts are correct, the winter thaw we’ve all been waiting for is about to begin this weekend.

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Winter thaws are when most of the phosphorus enters our lakes and streams from “nonpoint” or “runoff” pollution.

 

 

 

 

 

 

 

As managers of landscapes, we need to keep in mind that: [Read more…]

Turf Green-up Underway

It has been a long winter and delayed spring this year but yesterday’s rain and that of two weekends ago has “primed the pump” and initiated new growth of many turfgrasses and other plants. Thus, there is no more time to put off yard clean-up. Any leaves, branches and other debris dropped and blown around during the winter should be removed from turfs and other lowing growing landscape plantings. Otherwise early spring growth of plants will be impeded by any debris smothering those plants.

20140330_094107 (640x360)There has been little to no leaf growth of turf to this point, so mowing isn’t needed other than for help in picking up or mulching tree leaves.

For turfs forming a complete and dense ground cover, there is no urgency to fertilize. Let the grass wake up in response to warmer weather and rain. If it is important to get the grass growing, apply low to moderate (0.25 to 0.5 lb. per 100o sq. ft.) rates of nitrogen fertilizer. Fast acting fertilizer will obviously encourage more rapid green-up. Some examples of fast acting N included ammonium sulfate, blood meal (natural organic), fish meal (natural organic), and urea. Do not apply more than 0.5 lb. per 100o sq. ft of a fast acting fertilizer at this time. Over-applying nitrogen in the spring could result in extremely fast growing grass once the weather warms into the 60 to 70 degree F range. It is also increases the risk for nitrogen leaching in locations where that is a concern.

20140405_124606 (300x169)For turfs that have poor ground cover, be aware that soil erosion will be a serious risk at this time of year. Soils are wet and easily eroded during intense spring rains. Remember that soil erosion and water runoff from bare ground can carry nitrogen and phosphate into our waterways, contributing to the eutrophication process. Take action to stabilize the soil in these areas. If turf is the intended vegetative cover, apply a seed blend or mixture containing perennial ryegrass to these areas to re-establish cover and stabilize the soil. Perennial ryegrass will germinate under cool soil temperature and is useful in re-establishing cover. If you want to delay seeding until the weather is warmer, cover these areas with a wood mulch to reduce the soil erosion and runoff that will occur during each rain.

Drought Ends in New Jersey

Last autumn I was blogging about the drought conditions that we were experiencing. Thankfully, this winter’s precipitation, albeit lots of snow, has changed our water status in the region. The U.S. Drought Monitor no longer lists New Jersey as having abnormally dry or moderate drought. You can view more details at http://www.nrcc.cornell.edu/page_drought.html

Expect I will have to post about snow mold disease and flooding, once we get a thaw.

The current drought monitor map of the Northeast.

The current drought monitor map of the Northeast.

Dormancy in October? It is very dry and cool.

I spent a couple days this past week teaching in a turf care training program at Central Park in NYC. Many lawn areas in Central Park that are not irrigated were entering dormancy because of the dry soil conditions. And as you look around there is an increasing acreage of turf as well as shrubs and trees in our area that are being challenged by drying soil conditions. Fortunately, it is cool and many plants are tolerating the drying by entering dormant.

Lawn area entering the onset of dormancy. Shoot growth is shutting down and leaves are wilting.

However, managers should think about their end of the season programs related to irrigation shut down [Read more…]

Dollar Spot Activity Flares Overnight

The high humidity of last night (28-29 May) caused dollar spot disease to escalate. Until last night, symptoms on unprotected susceptible turf were minor.

The cottony fungal growth (mycelia) of dollar spot, which is easily seen at early morning hours during wet humid weather.

Susceptible grasses grown under low N fertility will typically have [Read more…]

Slow Green-up of Kentucky Bluegrass

There are numerous elite varieties of Kentucky bluegrass (Compact Types) that have excellent tolerance of leaf spot, summer patch, and stripe smut diseases. Many varieties produce a very attractive, dense, compact (low growing) turf with dark green color during the summer.

Some elite varieties of Kentucky bluegrass exhibit slow spring green-up (plot in center foreground).

[Read more…]

Slow Growth This Spring

Slow growth of grasses has been a common complaint this spring. There are many factors that can cause this but cool dry weather has been a major factor this year.

Slow growth of turf can be due to many factors but cool dry weather has been important this spring.

[Read more…]

Risks to Soils and Plants from Saltwater Flooding

As you might expect, we are receiving questions from county agents, landscapers, and property owners about saltwater flooding effects on soils and plants and the appropriate remediation. The information below may be helpful in answering these questions. (Thanks to Stephanie Murphy for pulling together a lot of this information).

Problems from Saltwater

There are a number of potential problems caused by saltwater including: i) the direct effect of burn (osmotic stress) on plant tissue; ii) dehydration of plants (physiological drought stress) caused by increased osmotic potential in soil; iii) plant damaged by sodium (Na) toxicity; iv) loss of soil structure caused by excessive Na; and v) soil infertility caused by increased soil pH (excessive alkalinity). [Read more…]