Maybe you should post your question in the organic lawn care forum since you're only interested in organic solutions.

Only go to the organic side if you never want an answer... All they do is post the same generic garbage repeatedly. Worms eat thatch & a dethatching machine will only work the top inch or so of soil. Any ideas why your thatch has gotten so thick?

If the sod is less than a year old and it came from any half decent sod farm, it is highly, highly unlikely that there is thatch.

Normally, I'd suggest that you take out a 4" deep wedge and look at a cross section and compare it to a google image of thatch, but with new sod, it would be too easy to confuse the shallow sod root zone with the distinct horizon between a true thatch layer and root free soil beneath it.

See pics of thatch in this slide show--also chart on effectiveness of bio products

Is there a "problem" (appearance?) with your turf that makes you think you have a thatch problem?

It will help to know where you live, a nearby city. I'm not familiar with Pennblue sports turf. Is it a standard cool season sports turf--a mix of KBG and rye?

Does your dedication to organic preclude any synthetic alternatives, including fertilizers?

Do you have dogs? What have you done since last October-fertilizing, mowing height, pre or post emergents, fungus control, watering? When and how much. There are some people here that can give you some effective organic options, but in some cases only a synthetic will perform.

I'm not familiar with Cali and your climate, nor am I familiar with Sustane products, but a couple of observations:

The Sustane label states it is 1.25% Fast Release Urea and Ammoniacal Nitrogen (not sure of that terminology other than it's used to generally classify urea and ammonium fertilizers and also used in describing water pollutants.) Nevertheless, for every one pound of N, 25% is fast release. Now my quandary, the other 75% is described as Water soluble organic N. Water soluble indicates fast release. Normally organics are described as water insoluble, or slow release. Maybe one of the organic folks or chemist can help with clarifying that. In addition that product contains significant percentages of P and K and sulfur.

Anyway, whether fast or slow, one pound of N very 6 weeks is excessive and actually could/would promote thatch growth. Ideally N application for KBG is 3-5# annually.

I would suggest that you adjust your feeding to once in late May, once your Summer ends in late August-September and then a winterizer if your lawn stops growing during your "winter". Otherwise, if you have no winter where the lawn stops growing, you could feed again in October and again in early December. (if I correctly remember the schedule for KBG in mild climates.)

I would defer to input here from someone more familiar with turf (KBG) in the Bay area.

Those brown spots, where you suspect disease. look at the grass blades on the still green grass where the brown transitions to green and use this to identify any lesions.

If you do have thatch, you should address it now or the turf will suffer badly (disease, insect, and water deficiency) this Spring and Summer.

I would also recommend you have a soil test done. A very good lab is loganlab.com.

Wow. Now I think I see where yardtractor1 got his question about the Sustain product. Sorry if I went the wrong direction on that.

Classic thatch conditions. Too much water and too much fertilizer. Here are the basics of lawn care. Normally I would not post these except for someone new to lawn care, but you're "in violation" of some biggies. The result is the thatch, disease, and poor color.

Basics of Lawn Care

After reading numerous books and magazines on lawn care, caring for lawns at seven houses in my life, and reading numerous forums where real people write in to discuss their successes and failures, I have decided to side with the real people and dispense with the book and magazine authors. I don't know what star their planet rotates around but it's not mine. With that in mind, here is the collected wisdom of the Internet savvy homeowners and lawn care professionals summarized in a few words. If you follow the advice here you will have conquered at least 50% of all lawn problems. Once you have these three elements mastered, then you can worry about weeds (if you have any), dog spots, and striping your lawn. But if you are not doing these three things, they will be the first three things suggested for you to correct.

1. Watering
Water deeply and infrequently. Deeply means at least an inch in every zone, all at once. Infrequently means monthly during the cool months and no more than weekly during the hottest part of summer. Do not spread this out and water for 10 minutes every day. If your grass looks dry before the month/week is up, water longer next time. If that does not work, then you might have to water more than once per week during the summer's hottest period. Deep watering grows deep, drought resistant roots. Infrequent watering allows the top layer of soil to dry completely which kills off many shallow rooted weeds.

You will have to learn to judge when to water your own lawn. If you live in El Paso your watering will be different than if you live in Vermont. Adjust your watering to your type of grass, temperature, humidity, wind, and soil type. It is worth noting that this technique is used successfully by professionals in Phoenix, so...just sayin.' The other factors make a difference. If you normally water 1 inch per week and you get 1/2 inch of rain, then adjust and water only 1/2 inch that week.

2. Mowing
Every week mulch mow at the highest setting on your mower. Most grasses are the most dense when mowed tall. However, bermuda, centipede, and bent grasses will become the most dense when they are mowed at the lowest setting on your mower. In fact there are special mowers that can mow these grasses down to 1/16 inch. Dense grass shades out weeds, keeps the soil cooler, and uses less water than thin grass. Tall grass can feed the deep roots you developed in #1 above. Tall grass does not grow faster than short grass nor does it look shaggy sooner. Once all your grass is at the same height, tall grass just looks plush.

3. Fertilizing
Fertilize regularly. I fertilize 5 times per year using organic fertilizer. Which fertilizer you use is much less important than numbers 1 and 2 above. Follow the directions on the bag and do not overdo it (unless you use organics in which case you may overdo it without fear of hurting anything).

At this point you do not have to worry about weed and feed products - remember at this point you are just trying to grow grass, not perfect it. Besides once you are doing these three things correctly, your weed problems should go away without herbicide.

So for right now I would stop watering and let the soil dry out. For the thatch I would spray it with liquid molasses at the rate of 1 gallon per acre (3 ounces per 1,000 square feet). Molasses will feed the bacteria and fungi that decompose thatch so that they multiply and, hopefully, take care of the thatch without the machine. If that does not work, then you can still use the machine in the fall. You should be able to buy molasses at wholesale rates at a farm and ranch co-op (not a normal feed store). The co-ops sell products by the pound. Molasses fluctuates but runs about 10 cents per pound. A gallon is a little more than 10 pounds. Bring your own container (milk jug or liquid laundry detergent bottle is fine). Here's something else I just wrote about watering.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

I think you'll see a big improvement just fixing the water.

The Sustain product is not a great organic, in my opinion. I'm assuming you use the one with turkey litter and feathers. Since you have so much room to play with, you might do a test to compare that product with something like alfalfa pellets (rabbit chow or chinchilla if you can get it). The application rate is 15 pounds per 1,000 square feet. Put them down side by side with some sort of marker to be sure which is which. Give them both a month to work and see which you like.

If you want to get rid of the fungal spots, try ordinary corn meal, not corn gluten meal. Call your local feed stores or co-op. It comes in 50-pound bags and should cost well under $10 per bag. The application rate is 20 pounds per 1,000. Corn meal is also an organic fertilizer, so expect to see some greening where you use the corn. Corn works by attracting a beneficial, predatory fungus which decomposes the disease fungus. You should see improvement in 3 weeks.

You can apply any and all of these materials on the same day, rain or shine, if you like. If you have questions about what I've written and/or where I conflict with other things you've read or heard about organics, please write back. I have reasons for my opinions...and I'm always willing to listen and learn.

Thatch can, in and of itself, be defeated by feeding organically (consistently) over time with any grain, Milorganite, and so on. It takes time, so very severe thatch problems may require an initial dethatching. Really, that can be done chemically with molasses, a bit of soap, and some liquid with a fair clip of nitrogen in it--MiracleGro or kelp come to mind.

As David noted, properly watered and fed lawns get less thatch, but some grass types (notably Zoysia and Kentucky bluegrass) simply produce enormous amounts of thatch (Zoysia being by far the worst).

We'll I guess maybe we ran him off...OP? Maybe he's out dethatching that soccer field.

Strange. Well, hopefully, they will check with the manufacturer of the gopher netting before aerating. Just learned that they also sell a netting made out of galvanized wire or stainless steel besides the plastic mole netting I've seen and assumed it was.

David, NP, but I'd still like to hear your take on the water soluble organic N on the other thread.