Organics don't really work the way synthetic (high NPK) fertilizers work, it's comparing apples to oranges. Both will do the job, but organics act slower & last longer by stimulating the soil organisms. If you live somewhere with a short growing season, that may not work. I use a combo of synthetics & organics throughout the year

I'm not sure I will be helpful in clarifying this for you. I can give you a few of the facts, or at least the thoughts which are thought to be facts.

Organic fertilizers can be used any day of the year, or every say of the year, with no problems. When you overdo organics the worst thing that happens is you get the aroma of sour milk.

Organic fertilizers are made of food. If you look on the list of ingredients you'll see alfalfa meal, soybean meal, corn meal, cottonseed meal, feather meal, bone meal, animal byproducts (often poultry manure), and rarely, blood meal. Most of these materials are available in 50 pound bags at your local feed stores. If you want to save some money you can buy them at the feed store and apply at the rate of 15 to 20 pounds per 1,000 square feet.

The NPK of organic fertilizer depends on the ingredients of the fertilizer. Each of those feeds has a different composition and thus a different NPK. But more importantly the NPK of organic fertilizer is irrelevant. NPK has to be on the label because fertilizer labels are regulated by the chemical fertilizer industry. What is more important in organic fertilizer labels is the food content. Most important is the protein value because protein contains nitrogen molecules. If you are worried about P and K, then you can mix up the materials you apply. The total application rate remains 15-20 pounds per 1,000 square feet.

Organic fertilizers rely on the biology in the soil - microbes like bacteria, fungi, and microarthropods (teensy insects). Their food chain is so interactive and complicated that it is referred to as the Soil Food Web. The microbes consume the organic fertilizer and other microbes consume those consumers ad infinitum.

Organic fertilizers are all slow release because it takes the soil biology 3 weeks to process the fertilizer into plant food. Feather based fertilizers take longer to process to 3 months is a much slower release. I suspect the Safer and Purely Organic products are feather based due to the higher N value. There is an exception to the slow release material. Blood meal is extremely fast release. It is so fast that it must be used sparingly. Some fertilizers will mix a small amount of blood meal with feather meal to get a more sustained release over a long time.

The multi step programs are based on sustaining a cash flow throughout the year. The MBAs at Scott's sat back and asked the question, What can we sell every few months that will keep our name in front of the public and our products in their garages? They came up with a 4 (sometimes 5 or 6) step program dealing preemergent/fertilizer in the early spring, seed in mid spring, weed n feed in late spring, insect control in late summer, and fertilizer and seed in the fall. This type of program gets you hooked on their products. It's frickin genius marketing. Unfortunately it is a huge waste of resources and a litany of environmental mistakes. Fertilizing in the early spring is a mistake, because it forces the plants to release stored nutrients before they need them. Seeding in the spring is a mistake because spring germinated seed does not develop strong roots before the summer heat kills them off. Most lawns don't need blanket herbicide in the spring. All they need is spot spray of a few weeds. Most lawns don't need insecticide in the summer - ever. All most lawns need is fertilizer in the late spring, again in early fall, and again in late fall. I believe the use of preemergents is a crutch for people who forgot to get a dense lawn back in the fall. It also seems to be good for bermuda lawns because they are mowed very low which will expose soil to the sunlight in the thin spots.

Do you have specific issues with your lawn or were you just looking for answers about the various fertilizers?

Thank you for the extremely detailed response! I don't have specific issues, just looking for general answers. I'd love to go the Milorganite route, but I have a big lawn (20,000 sq ft) so it gets a little pricey, and I just wanted to make sure I wasn't missing out any any nutrients by going with a product that has a 0 in it all year long. As for weeds, I do have some problem spots so I believe (for now anyway) that a pre-emergent (crabgrass and broadleaf) is required. Thanks again.

I believe the use of preemergents is a crutch for people who forgot to get a dense lawn back in the fall.

Now that's a little mean-spirited. Try growing cool season grass south of the Mason-Dixon line without pre-emergent and see if you can beat back the crabgrass in the summer, thick lawn or not.

I added price points of the ones you listed per pound and cross referenced with a synthetic.

Safer Brand 25 lb. Ringer Lawn Restore II Fertilizer 10-0-6, $147 =5.88 alb

Purely Organic Products 25 lb. Lawn Food Fertilizer 10-0-2, $101 =4.04 a lb

Milorganite 36 lb. Organic Nitrogen Fertilizer 5-4-0, $104 =2.8 a lb

GreenEdge 40 lb. 6-2-0 Slow Release Organic Fertilizer 6-2-0, $173 = 4.3 a lb

Your organic winner is "Purely Organic Products 25 lb" (this is the best bang for your buck if you want to do it organically)

and to cross reference that with a synthetic fertilizer.

Average price around here for a synthetic grass fertilizer is about 0.50-0.75 cents a lb with an NPK of 30, 0, 3. (I see them go as low as 35cents a lb)

For your best value organic fertilizer (Purely Organic Products 25 lb) to match the output of a synthetic, you're looking at a whopping 12.12$ per lb!! as apposed to 0.75 cents a lb for a synthetic. (I hope this puts things into perspective for you so that you can more wisely make a decision that will fit your needs)

And just to clarify the usage. 1 recommend application of a synthetic fertilizer is more then enough for a year at (30,0,0). You could stagger that and use half the recommend dose, and apply twice a year. for an NPK ratio of 15,0,0. which works out to the same cost of course.

BTW the last 2 numbers in the NPK are insignificant to established grass because most soil tests find that P and K are adequate enough for grass growth. That's why you'll normally see the P and K with low values. In addition, grass uses very little P and K once established.

Sometimes cost is more of a game than it is a barrier for people's lawn hobby. Cost is interesting in simply trying to minimize it. Whether it is $1,000 per year or $100 per year is less important than just getting the minimum. However, if total cost of using organics exceeds your lawn hobby budget, then going with a chemical fertilizer might be less expensive. At that point you have to do the math.

The best way I've found to compare costs is to measure cost to apply the product over 1,000 square feet. Any other cost measurement requires knowledge of chemistry and conversion of protein to NPK which is really not a good way to measure the effectiveness of organic fertilizer.

The cost for alfalfa pellets ($15 for 50 pounds) applied at 15 pounds per 1,000 square feet is $15/50 pounds x 15 pounds/1,000 square feet = $4.50 per 1,000 square feet. Fastnk, would you mind rerunning your cost calc per 1,000 square feet? I'm not disputing your eventual conclusion, but your method is very confusing.

One of the gurus emeritus of this forum, Texas Weed, owned and operated a sod farm where he used only synthetic fertilizers. The cost of organic fertilizer on a large scale would have made his grass too expensive to sell in the Texas and Oklahoma markets. But at home he used only organic fertilizers. The difference in scale from home to farm made the difference for him. If you are not trying to make a profit from your lawn, then you can spend whatever you want to spend and just enjoy it.

Thanks everybody. Cost isn't the major factor for me in deciding what to use, as I believe it could be as low as $400/year for Organic (i.e. 1 bag of Milorganite covers 2,500 sq ft, so I need 8 bags @ $13/bag = approx $100, x 4 times/year = $400). vs. approximately $300 (maybe a little less) for a 4-step Scotts (just as an example).

Again, it's more trying to figure out if I'm missing out on needed nutrients if I don't go with a synthetic, since the organics have 0 of something (of course I could mix and match organics and then not have a 0 anywhere). For example, I could use one of the ones with 0 P for 3 treatments, but when I seed use Milorganite which has some P (which I believe is what I want a lot of when seeding?). Or, again, is it drastically better to use something like Lesco Starter Fertilizer when I seed, as it's 18-24-12?

Thank you all again!

I have recently become interested in mycorrhiza, which is one of the soil web fungi. It effectively lengthens the reach of roots many times, enabling the plant to receive more nutrients and water than their roots alone could gather. Here is an introductory article. One of the benefits is how mycorrhizae can obtain phosphorus which is often present but unavailable because it's fixed with a metal. (Unavailable phosphorus does not show up on a soil test.) It makes the unavailable available. Other benefits are better drought resistance, better disease resistance, better soil aggregation. It would be wonderful to have lots of mycorrhizae. One of the things that inhibits them is soluble phosphate fertilizer. If there are lots of available nutrients, the mycorrhizae take a vacation. It seems that mild stress, the plant beginning to sense lack of nutrients or water, encourages growth of the mycorrhizae. Anyway, in relation to the discussion about what kind of fertilizer to use, keep the fungi in mind. Too much of any kind can impact them. Some general things about fertilizer: the organic kind works best when it's warm weather. In late fall the microbes are not active so synthetic would be better then. Synthetic can be used in place of organic but you do miss out on feeding the soil life if you use just synthetic. In light of what I'm finding out about mycorrhizae, I suggest aiming for minimum amounts (whether organic or synthetic), especially of phosphorus. Leaving your grass clippings on the lawn can reduce fertilizer use by 25%. If you have access to feed stores, using one of the grains, like Dchall suggests, is probably the most cost effective way to do organic feeding.

Becky, your check is in the mail ;-)

I was going to write a response, but it gets so involved. Maybe this will help a little:

http://store.parsonspestcontrol.com/msds/12-6-6-w64-nitroform-micros-3month-msds.pdf

Cost isn't the major factor for me in deciding what to use, as I believe it could be as low as $400/year for Organic (i.e. 1 bag of Milorganite covers 2,500 sq ft, so I need 8 bags @ $13/bag = approx $100, x 4 times/year = $400). vs. approximately $300 (maybe a little less) for a 4-step Scotts (just as an example).

The cost savings for granular fertilizer over organic can be significant. Using the Vigoro 29-0-4 as an example, and targeting the same 0.75lbs N/thousand that you get from Milorganite at bag rate, you're looking at a cost of about $150 per year vs $400/year with Milorganite. You can probably get under $100/year if you hit an agricultural supply store. Also much easier to apply 1 bag of granular fertilizer than 8 bags of Milorganite, or 400 lbs of alfalfa.

With the remaining $250-$300 you can get yourself a nice pull behind sprayer that will further save you big money on pre-emergents on herbicide applications.

There's not evidence that additional organic input (especially "foreign" inputs like sewer sludge) in addition to grass clippings and root exudates, is beneficial or desirable. In addition, Milorganite comes with a variety of "pharmaceuticals" found in sewage like triclosan which accumulate over time in the soil. If you're going to go organic, I'd suggest alfalfa (possibly mixed with some urea to get some fast N) rather than Milorganite.

Again, it's more trying to figure out if I'm missing out on needed nutrients if I don't go with a synthetic,

Your soil test will tell you if your soil lacks phosphorus or potassium. Maybe you need some, maybe you don't. As for P at seeding, the reason for more P then is to make sure there's some close to the seed as P is immobile in the soil and while there may be plenty down in the soil, there may not be much on top where the seed is. Milorganite will take about three weeks to be processed by the soil organisms before the nutrients become available. Your seed will take 1-3 weeks to germinate, depending on what kind it is. If your soil tests high in phosphorus, it's likely there's phosphorus at the surface as well as down below. Why don't you see what that says before deciding on what to get? It's good to be conservative.