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…]

Weather Ideal for Pythium and Brown Patch

The weather this summer has been very conducive for brown patch and Pythium blight diseases. I have received number requests this summer to address turf problems related to one or both of these diseases in lawns, sports fields, sod and now my own plots.

Suspected initial outbreak of Pythium on velvet bentgrass maintained at a 0.110-inch height that occurred over the weekend (August 7) in a cultivation trial at Hort Farm No. 2 in North Brunswick NJ.

Suspected initial outbreak of Pythium on velvet bentgrass maintained at a 0.110-inch height that occurred over the weekend (August 7) in a cultivation trial at Hort Farm No. 2 in North Brunswick NJ.

The weather forecast for the rest of this week indicates [Read more…]

Kyllinga Awakens as Soil Temps Increase

Daily high soil temperatures at the 2-inch depth are consistently getting into the 60s °F. Yesterday, temperatures in sunny locations reached into the upper 60s. This means that the warm-season species are, or will be soon waking from winter slumber.

Leaf tips emerging from rhizomes of kyllinga on 15 April 2015 in central New Jersey.

Leaf tips emerging from rhizomes of kyllinga on 15 April 2015 in central New Jersey.

For the last three weeks, I have been watching the emergence of false green kyllinga (Kyllinga gracillima). Most sites infested with kyllinga are probably showing active shoot growth. So it appears that kyllinga needs soil temperatures that reach consistently into the 60s to emerge from winter dormancy. As temperatures continue to warm, re-growth of kyllinga should accelerate.

False green kyllinga is a perennial sedge species with well-developed rhizomes (underground lateral spreading stems). Kyllinga is relatively low growing so it [Read more…]

Looks Like Grass… But It Isn’t

Other than today and yesterday, soil temperatures in New Brunswick have been reaching into the lower 50s °F during the last week or so. And you see the effects, some plants are finally awakening from winter slumber. Cool-season turfgrasses are slowly greening up. Tree buds are swelling, some are flowering. Forsythia is just starting to bloom. And prostrate knotweed, one of the earliest germinating summer annual weeds, is emerging.

Prostrate knotweed is frequently found invading [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.

The 2014 Rutgers Turfgrass Research Field Days Sets Attendance Record!!

The annual event, held on July 29-30, highlighted ongoing turfgrass research at Rutgers and was attended by over 800 industry professionals! Read the full story here.

Localized Drought Stress is Here

As stated in an early post, summer stress is developing throughout the state. Summer stress isn’t widespread or severe but it is developing, particularly wilt stress, within very localized areas of many landscapes. Landscapes that receive little to no irrigation are especially prone to wilt and drought stress right now.

It is important to scout and assess the severity of any wilt stress in moderate-to-high value areas of the landscape. Hours are important, don’t put off the scouting of wilt stress. Assuming the grass or other plants will tolerate wilt stress without confirming the severity of the situation can lead to severe drought stress and stand loss at this time of year.

Symptoms of subtle wilt stress on June 22. Healthy turf will likely to tolerate this level of wilt stress.

Symptoms of subtle wilt stress on June 22. Healthy turf will likely to tolerate this level of wilt stress.

 

 

 

 

 

 

Grasses such as the fine fescues and annual bluegrass will be [Read more…]

Crabgrass Emerging

Crabgrass has been emerging for several weeks now, depending on the exposure. Warmer and more open turfs will likely have more advanced (larger) plants while cooler and denser turfs will have smaller plants.

Relatively small crabgrass plants  (most pre-tillering stage) emerging from a footpath on June 11th.

Relatively small crabgrass plants (most pre-tillering stage) emerging from a footpath on June 11th.

 

Management options for this weed at this point in the season range from doing nothing to [Read more…]

Tis the Season for Summer Stress

Optimum growth of cool season grasses occurs within the temperature range of 60 to 75 °F. Yesterday, the New Brunswick weather station indicated that soil temperature at 2 inches exceeded 75 °F for more than 12 hours and peaked at 82 °F.

This doesn’t mean that grasses will soon be dead. But it is a signal to be watchful for summer stress problems.

Summer stress is often a combination of multiple stresses. Localized drought, ponding of water, diseases, insect pests, poor culture (mowing, fertilization, and irrigation) and other stresses combined with high temperature stress can challenge the health and persistence of cool season turfs from now through the end of summer. It is important to avoid situations that compound too many stress at the same time.

For example, now is the time [Read more…]

Right On Cue: Dollar Spot Disease

Exactly like Dr. Bruce Clarke teaches, Memorial Day arrives and so does dollar spot disease.

Symptoms appear as round, brown to straw-colored spots approximately the size of a silver dollar. On short cut turf, the spots with advanced damage can become somewhat sunken. At taller cutting heights (greater than 1 inch), the damaged spots are larger and more diffuse.

Highly susceptible grasses will be the first to exhibit symptoms including annual bluegrass, creeping bentgrass (depending on cultivar), and perennial ryegrass. Tall fescue and most Kentucky bluegrasses will be more tolerant of this disease.

Cultural techniques that can suppress dollar spot disease include disruption of dew and guttation water in the morning and increasing N fertility (if it is low). Mowing early in the morning (disruption of dew) should also be helpful.

Creeping bentgrass entries in Dr. Stacy Bonos' evaluation trials that are highly susceptible to dollar spot disease appear in the image foreground.

Creeping bentgrass entries in one of Dr. Stacy Bonos’ evaluation trials that are highly susceptible to dollar spot disease (image foreground).