What OM should I aim for and whats the best way of boosting that? You really cannot do much about it except to mulch mow, and keep a healthy lawn. As time goes along the OM will rise, but we are talking decades when it comes to a lawn. The higher the better, but for grass it does not need to be real high. 3 to 5% is more than adequate for a lawn. To be factual, you do not need any OM to grow grass. Take a look at most high end golf course greens or professional sports fields with grass and there is not a spec of OM or any soil whatsoever. Where it does really matter is vegetable and flower bed gardens. But in those areas you can boost the OM pretty easily by adding several inches of compost every year. You cannot do that with a yard. You would go broke trying and smother the grass.

Hello all, I'm a first-time poster here in the Lawn Care forum. I'm an avid gardener but still consider myself a newbie--especially when it comes to lawns. I just got the results from my soil test from my local UT Extension & would appreciate your help with developing my plan for the coming seasons. The lawn I currently have is maybe 50% common Bermuda, which I hate and would like to eliminate. The remainder is probaby 25% tall fescue which I've overseeded and tried to keep the Bermuda from choking out, and the last 25% is weeds: crabgrass, dandelions, wild strawberries, and an awful lot of purple deadnettle in the winter. I had great results from overseeding in the fall last year. But I'd like to spread pre-emergent to prevent the forest of purple deadnettle I had last year. So when should I overseed fescue relative to spreading pre-emergent? Same sort of balancing act goes for spring... I need to spread pre-emergent for general broadleaf weeds, but would also like to try (for the first time) something to suppress the Bermuda. Will fall-seeded fescue be able to stand up to those herbicides in the spring? And would a fertilization schedule (which has been recommended by my county extension) need to be altered according to these factors? FYI: Irrigation is not an option outside of extreme circumstances. I don't have the infrastructure in place, nor the funds to put it there. And to be honest, no one around me has it either and (some of) their lawns look fantastic. I'm in Middle TN, slightly northwest of Nashville, zone 6B. Soil is mostly clay, but getting better as I mulch-mow grass & leaves into the turf. (This year I've been mowing at ~3.75" which has noticeably helped the fescue.) --- Soil Test results: (Note that I selected turf type as "Lawn, Cool Season". My rationale was that I want to know what helps the fescue the most--not what helps the Bermuda the most.) Water ph - 6.5 Phosphorus - 51 (high) Potassium - 183 (high) Calcuim - 1562 (sufficient) Magnesium - 142 (sufficient Recommendations: Lime is not recommended at this time. II. Medium Level Maintenance of an established lawn. Topdress annually Sept. 1 with 6.2 lbs of 16-4-8 or (other amounts of similar-ratio ferts here... I don't need to type them all out.) per 1000 sq ft. Topdress annually Oct 15 with 3.5 lbs and Mar 1 and Apr 15 with 1.75 lbs of 34-0-0 (or other similar ratio) per 1000 sq ft. If the fertilizer contains at least 30 percent slow-release form of nitrogen, the Mar and Apr applications can be combined as one application in March. --- So, ye masters of all things lawn care... any thoughts regarding the timing of: Fall overseeding Fall application of pre-emergent (mainly targeting deadnettle) Fall applications of fertilizer recommended by my county extension Spring application of fert recommended by extension Spring pre-emergent Spring application of (something like Fusliade or Acclaim?) for Bermuda suppression And one more noobish question... how can I tell which ferts are slow-release and which are not? Thanks in advance for answering my million questions. I've already learned so much from you guys; I'm just trying to tie it all together. :-) --Jon

Well, since you're talking turfgrass, your options are somewhat limited. There's really no practical way to increase the OM in the soil in the near term. Keep mulch mowing. According to the folks at OSU's REAL, you're in the right range except for high pH, very low P and somewhat low K (link below to their Acceptable levels for lawns). Your dilemma is lowering pH while increasing P. First, before you take anyone's advice I would encourage you to discuss the results with your local county Ag extension agent. He/she will have local knowledge and can better steer you than about anyone else. With that as a caveat, I believe what you want is an ammonium phosphate fertilizer (e.g. MAP @ 11-52-0 or DAP @ 18-46-0 ), and then separately potassium sulfate (sulfate of potash) to bring the K in line. All should be available from local ag/farm supply or feed stores. But, don't take my word for it - talk with your county agent first. Here is a link that might be useful: Interpreting a Soil Test for Lawns

According to my calculations, you are short about 2 lb/k of P2O5 (phosphorus) and 4 lb/k of K2O (potassium). Probably the easiest way to get that 4 lb/k of potassium is to use a balanced NPK fertilizer, like 10-10-10 or 20-20-20. It would also give you 4 lb/k of nitrogen and 4 lb/k of phosphorus. You don't need that much phosphorus but it won't harm anything (except possibly the mycorrhizae). You want to avoid nitrogen in the summer. So if you went with the balanced fertilizer, you would be applying probably 3 applications, one a month for mid August, September, October. The 4th could be next year. Divide the NPK number into 100 to get the application rate (example, for 10-10-10, divide 10 into 100 to get 10 lb/k rate). An alternative is to find SOP, potassium sulfate, 0-0-50. You could apply that once a month, even in the summer, at 2 lb/k for four months. That would take care of the potassium. Two applications of starter fertilizer in the fall would take care of the phosphorus. Since you're planning to overseed, it would make sense to use this plan, as you could do an application of starter fertilizer at seeding and another a month later. Milorganite could substitute for the second application of starter in the fall. Use bag rate for starter or 25 lb/k of Milorganite at 5-4-0 to get 1 lb/k of phosphorus. As for nitrogen, the balanced fertilizer plan would give you 4 lb/k, which is more than you need for the year considering that you have already applied nitrogen this spring. If you use the alternative plan (which I think is better), you would get almost a lb/k with each application of starter fertilizer (1.25 with Milorganite at 25 lb/k) and then you could do a winterizer application of a quick release nitrogen in late fall after the grass has stopped growing but before the ground freezes. That would get you off to a good start next spring, when you could hold off on fertilizer until around Memorial Day. Your organic matter is low. It's good to leave clippings on the lawn when you mow. This fall mulch mow any leaves in your neighborhood that you can gather. If this is new construction, there may not be many trees but do what you can. The compost you're planning will help. Mulch mowing leaves is like making your own compost for the lawn --and you don't have to spread it! Water in your applications. Milorganite does not need to be watered in. Phosphorus tends to get tied with quickly with calcium in alkaline soil. It's there, just not available to the grass. Using organic forms of phosphorus, like Milorganite, enables a slow release of phosphorus. If you test next year and phosphorus is low, it's probably because of the alkaline soil. It's still there, just unavailable. Such is life for alkaline soil.