A. Parts of the turfgrass plant.

Know the terms blade, C₃, chloroplast, diffusion, Eragrostoideae, evapotranspiration, fibrous roots, glumes, intercalary meristem, pollen, respiration, rhizome, root hair, spikelet, stigma, stolon, sunlight, thatch, translocation, water

Also know anther, auricle, carbon dioxide, chlorophyll, collar, cuticle, fertilization, fibrous roots, floret, hybridization, inflorescence, internode, leaf, lemma, midrib, node, ovary, palea, phloem, photosynthesis, pistil, seed, sheath, shoot, spikelet, stomate, sugar, tiller, vein, xylem

B. Thatch is an important component of the turfgrass community.

Thatch is one step on the way toward forming decomposed organic matter, and the recycling of nutrients. By the way, what is thatch? What is lignin? How can thatch deposition be slowed (fertilization, irrigation, pesticides)? What are its benefits? What are its problems (physical, biological, chemical)? Other considerations: time, disposal fees, environmental problems.

C. Shade is the most universal problem in growing urban grasses.

How shady is shady? Primary factor (light intensity, quality) vs. secondary factors (root competition with trees, microenvironment, leaf succulence, evapotranspiration, diseases, insects) Direct management approaches (tree pruning, reduced fertilization, increased mowing height, litter removal). Integrated management considerations (lessening traffic problems, ecological grouping of vegetation).

D. There are basic design differences between warm-season and cool-season grasses.

Differences in suitability to insects, differences in cutting characteristics, differences in water use and heat tolerance, and wear tolerance are derived from the anatomical and physiological commitments. Physiological adaptations of different kinds of turfgrasses relate to their problems from shade, mowing, and traffic.

E.. Each region has several old "standbys".

Efforts to introduce species outside their normal climatic range are usually disastrous. You should know the major cultivars of Florida turfgrasses, their uses and limitations. We don't need another "miracle grass"; it mainly has to grow good. Purveyors of seeds have long tried to stimulate your buying appetite. Thanks to courageous gardeners, some new varieties are adopted every few years which turn out to be decidedly better than the old varieties. Unfortunately, for every 10 new varieties, probably only 1 or 2 is ever really a success.

F. Propagation.

While seed and vegetative propagation both offer advantages and disadvantages, both are effective biologically. In a strategic sense, the commitment to vegetative vs. seed has far reaching consequences. Seed propagation predominates in the cool-season grass areas, while vegetative propagation predominates in warm-season grasses.

A. There is a soil moisture "bank account".

By balancing the "bank account", scientists figure the current use of water by the turf. Factors such as soil type, natural depth of rooting, rainfall, and water use rate figure into when wilting occurs. Irrigation which is set by an automatic time clock can be adjusted or interrupted in response to changing conditions, thus maintaining an adequate supply of moisture. Many turfgrasses can be irrigated optimally when wilting begins. Thus a simple "bioassay" can be used.

B. Turf water use (transpiration) is governed by the physics of energy transfer.

The same number of kilocalories are required to evaporate a drop of water from inside a grass leaf, compared with a tree leaf, compared with a wet sponge, compared with an open body of water. When the sun doesn't shine, the process essentially stops. When the sun shines again, radiant energy is used to convert water liquid to water vapor. If the leaf did not lose water, it would overheat, and would not be able to exchange oxygen for carbon dioxide. You can't have your cake and eat it, too.

Except, cactuses and a few other plants have a way of doing their gas exchange at night, when the loss of water is reduced. Why don't they cook? In part, it is because they are thick and fleshy and their high mass can buffer against the accumulation of excessive heat. Why doesn't someone develop a cactus-like ground cover? They have. Ice plant and other succulents serve this purpose well. The only problem is that they grow so slowly that they are not capable of repairing themselves in response to traffic damage. Slow growth is also not a good strategy for competition against annual weeds, which may flourish during wet periods.

C. Microclimate (e.g., shade) has an overriding effect on water use.

The water use of Kentucky bluegrass has been shown to respond directly to the light level. Other microclimate factors that are very important in urban water use are wind, advective heat (e.g., sidewalks and parking lots), and relative humidity.

D. Grasses resist drought, but are not immune to using water.

Grasses have relatively shallow, fibrous root systems, which must be replenished about every 1-2 years, thus they are susceptible to the effects of periodic dry weather. Despite this, grasses predominate in regions with low rainfall, while trees and other woody plants predominate in regions with high rainfall. Grasses manage to survive dry weather by avoiding the effects of dryness. Some grasses escape by defoliating (losing their leaves). This conserves water only in the sense that there is none available to be lost. Most grasses have some way of partially protecting their stems and growing points from desiccation, thus they can regenerate after rain returns. If someone cannot wait for rain, but goes out with a hose and sprinkles the lawn, it is common to say, "turfgrass wastes water". In some communities, a brown lawn is becoming a badge of honor.

A. Reducing the size of a pipe does not increase the pressure.

Basics of friction loss, pipe size, and flow rate.

B. Sprinkler design: It is not possible to perfectly place a round peg in a square hole.

Reasonable design of sprinkler placement requires paperwork planning. Head-to-head coverage works best in most situations. Part-circle heads are used around perimeters, to prevent over-spray.

C. Spray drift and evaporation are not major reasons to avoid daytime irrigation.

The main problem is corruption of uniform spray pattern.

A. Fertilizer analysis numbers, e.g. "6-6-6" are not magic.

Fertilizer labeled "10-10-10" is the same for the lawn as the demonic "6-6-6". These two fertilizers have the same, balanced ratio of nutrients (nitrogen-phosphorus-potassium), yet some people feel that one or the other is good for the turfgrass. Which is best? Generally, the only difference between these two fertilizers is that the 10-10-10 has been bulked with inert material, such as sand, to create 6-6-6. If you really feel that 6-6-6 is best for the lawn, you can buy 10-10-10, and mix it, 3 parts fertilizer with 2 parts sand, to make your own 6-6-6! You would have more fertilizer, although it would not spread over any different sized area than the original 10-10-10.

There really are good reasons to consider one or the other fertilizer to be a better buy, and the main consideration is price per unit nitrogen. This is reasonable because nitrogen is the ingredient which is most expensive for the chemical factory, and most of the packaging efforts seem to be directed to conceal that the rest of what you are purchasing is mostly filler.

While the 6-6-6 fertilizer is almost always cheaper per bag, it is usually more expensive for the nutrients, after you account for its diluted concentration. It costs to add that sand, and then ship it sometimes hundreds of miles. If the 6-6-6 costs $4.50 per bag, and the bag is 50 pounds, then that will be $1.50 per pound of nitrogen. You are going to have to get the 10-10-10 for less than that, per unit nitrogen, or not more than $7.50 per bag, to make it the better buy. Usually the 10-10-10 is cheaper per unit nitrogen, but many people feel that the cheaper the bag, the better buy. Not true, but habits are hard to break.

There are extreme situations where a low-analysis fertilizer is better, but they are largely psychological. People get into the habit of dumping things on lawns, and usually the lower the analysis the less they are going to overdose it. Fertilizer overdosing can burn the lawn, because of the salt effect. Presumably a low analysis fertilizer is going to provide the same pleasant sensation of dumping something in great quantities, with less chance of burn. If you are not into massive overdosing, and don't mind calibrating your fertilizer spreader, then higher analysis fertilizers such as 16-4-8 or even 45-0-0 can be safely applied, and the results are just as satisfying.

As for the ratio of other nutrients, fertilizer distributors sometimes make the claim that their fertilizer is "balanced", because the 6-6-6 or the 10-10-10 analysis reflect an equal ratio of the three major nutrients. To the disappointment of those who want a balanced universe, the turfgrass doesn't know anything about the numbers. The "balanced fertilizer" ploy is even less balanced, when we consider that in most states the fertilizer laws require the analysis to be expressed as nitrogen, phosphoric acid, and potash; when converted to the pure elements N, P, and K, the so-called "balanced" 6-6-6 is actually more like 6-2.6-5.0. This is not balanced, and does nothing for devil worship, but it's all the same to the turfgrass.

B. Soil reaction (pH) influences the availability of nutrients and other chemicals.

In many soils, micronutrients such as iron and manganese are present but not available. In other soils, toxic elements such as aluminum are a problem, because the low soil pH makes the highly available. Soil reaction problems can be exacerbated by irrigation water and acid rain.

C. "Organic" fertilizer usually comes from chemical factory, not a cow.

It may seem strange, but "organic" fertilizer is usually founded on the chemical "urea" which has been produced synthetically in chemical factories. Due to conflicting definitions of the word "organic", many consumers mistakenly assume organic fertilizer is "natural", when it often isn't.

How do companies get away with calling their synthetic urea fertilizer "organic"? To the chemist, any compound such as urea with covalently bound carbon is "organic". Truth in labeling? Absolutely. Truth in marketing? No, not unless you are selling to first year chemistry students, who are supposed to know better.

Thanks to ingenious packaging and the miracles of chemistry, the chemical "urea" is an appealing, economical source of nitrogen (the mineral element used in greatest measure by the turfgrass). Unfortunately, the "unnatural" yet "organic" urea is 100% water soluble, quick release, thus it is more prone than several other nitrogen sources to be leached into the groundwater after the first heavy rainstorm. If you want "slow-release" fertilizer you should look for words such as "water insoluble" or "slow-release" on the label. If you want something "natural", look for words such as "cow" or "sludge" on the label. If it's natural, it is often slow-release.

A broader question is, "What is natural?" Is there anything unnatural? At the risk of opening a large can of worms, one brand of purist sees anything which is made by people to be "unnatural", while everything else is "natural". Is human sewage "natural", even though it is made by people? Does nightsoil become artificial once it is has been composted artificially by people? Or if composting is natural, because it involves organic processes, then what about adding the chemical "lime" to the compost stack, to help sweeten the process. Is that still natural?

D. Proper timing and accurate placement are the keys to fertilization.

Excessive leaching losses can occur in sand soils. In any soil, it may be inadvisable to apply high rates of N during rapid growth periods. Soluble fertilizers applied below the rootzone, e.g., before sodding, can be leached out of range. Phosphorus tends to be slowly moved, however.

A. Traffic is largely a problem of soil aeration and drainage, and wear tolerance is not so important.

B. Equipment is available to alleviate compaction and drainage problems, but it is also important to use proper design (soil materials, subsurface drainage, and grade) to facilitate good drainage.

C. Vehicular turf

Why not walk on the grass? (Wear, compaction, safety) Why walk, drive on the grass? (Natural air conditioning, groundwater infiltration, ambience, flexibility. How does the situation in southern Florida differ from most other areas of the United States? Design considerations for vehicular turf include drainage (and sand separates), load bearing, cohesion, traffic pattern, and safety.

A. The main reason to mow the lawn is to suppress weeds, and abort succession.

B. The temptation to scalp the lawn is great, hence the 1/3 rule.

Some grasses with vigorous rhizomes (such as zoysiagrass) can occasionally tolerate being cut to the nubbins. Most are severely damaged. Nevertheless, there is often a "hard-wired" reflex in people who cut grass to "push the metal to the stolon". The height of cut is intimately related to the frequency of cutting.

C. The grass leaf blade is a masterpiece of composite engineering, which explains why it is hard to cut.

Nature offers many examples of structures which are strong and light. The strength of the grass leaf blade is due to the way it can disperse damaging forces. Rotary mower blades must maintain a high tip velocity to cut evenly, and are still less efficient than reel mowers. The vast majority of the energy involved with mowing is used to propel turf clippings, and to account for losses of conversion and drive train losses.

D. Clippings do not contribute to thatch.

Turf clipping decompose rapidly, either in the lawn or as a great addition to compost piles. Either way, nutrients are recycled locally. Mulching mowers help alleviate the appearance problem.

E. Several types of mowers are available.

They include reel, rotary, and flail; when to use each; effects of a dull blade (frosted look, frayed leaf ends, disease susceptibility); their energy efficiency. How does a rotary blade cut grass? What kind of mower was described at the golf course? What kind of mower helps recycle clippings?

F. Mower safety

A. Nature abhors a vacuum.

B. So-called pests do not come from spontaneous generation.

Quarantine, sanitation are good preventative strategies. Digging an emergent weed species is probably more effective than chemical, curative strategies. A single weed can produce thousands of seedlings. Quarantine is most appropriate against fastidious organisms, and those with slow spread, e.g., patch diseases, rhizomatous weeds, and obligate nematodes. The concept of the "disease triangle" (encompassing favorable environment, susceptible host, and virulent disease organism=pathogen) can be extended from pathogens to other organisms, including insects and weeds.

C. Turfgrass diseases are most often fungi

D. Major turf insects are chinch bugs, caterpillars, mole crickets, and grubs.

Do you know what order each of these belongs to and what its main characteristics are (method of feeding, length of life cycle, part of turfgrass plant injured)?

E. A weed is a plant out of place?

A. High nitrogen availability seems to induce infestations of caterpillars and chinch bugs. Avoid summer fertilization.

B. Equipment tends to run in straight lines, thus maintenance of park-like settings is difficult.

Strategic grouping of landscape elements may not reproduce the ideal savanna, but is easier to maintain.

C. Pesticides.

D. Genetic resistance replaces the use of synthetic pesticides.

E. Problem solving.

Be able to solve turf performance problems through diagnosis, involving sample preparation, interviews, description of site conditions, management factors, turfgrass symptoms, and the interrelationship of this information to various classes of problems (soil and pests, including humans).

F. The symptoms are often more diagnostic of the host physiology than the pest.

Rapidly yellowing turf is often the symptom of a damaged root system, which may be due to brown patch disease, chinch bugs, or drought stress, and their effect on the shoots ability to feed the root.

A. Safety.

Know how turf practices harm people and other inhabitants of the environment and know how to minimize these deleterious effects.

B. Record keeping.

C. Conversions.

Be able to interpret turfgrass word problems and convert units of measurements by the chain method.