Don't panic. You're okay. You have not harmed anything. At the worst you will get a smell from too much protein in one place. And you have not really wasted your fertilizer. Organic fertilizer will decay at its own rate and feed your soil microbes as long as there is some on the ground.

There are much less expensive alternatives to Espoma if you are interested. Go to the Organic Gardening forum and look at the FAQ. The next to the last one is about organic lawn care.

There is only one organic fertilizer that will burn that I am aware of. That is blood meal applied too heavily. Unfortunately I can't help you with what "too heavily" really means. I think a starting point for blood meal application on a lawn would be about 5 pounds per 1,000 square feet. If that did not burn, I would feel somewhat relieved and use it at that amount. But blood is so seldom discussed on organic forums it's not worth much discussion. The only place you normally see it is as an ingredient in mixed-ingredient commercial bags.

No matter what you can't trust the settings on a spreader to apply the correct amount of anything organic. Some settings are close, but with organic, no settings are even close. You will have to calibrate your fertilizer to your spreader. Not to chastise you but if you know how much land you have to cover and how much the bag covers, most people will realize when they finish one bag and have only covered 1/4 of the expected area, that something is wrong.

Before I reply to your post, I'll reply to some of David's comments.

"There is only one organic fertilizer that will burn that I am aware of. That is blood meal applied too heavily."

Uncomposted poultry manure can also burn. I had access to uncomposted poultry manure many years ago and saw it burn when it was over applied.

"No matter what you can't trust the settings on a spreader to apply the correct amount of anything organic. Some settings are close, but with organic, no settings are even close. You will have to calibrate your fertilizer to your spreader. Not to chastise you but if you know how much land you have to cover and how much the bag covers, most people will realize when they finish one bag and have only covered 1/4 of the expected area, that something is wrong."

If I read the original post correctly, he had covered 1/4 of the area with 1/2 of the fertilizer. He realized something was wrong and posted here before making it worse.

IMHO, it doesn't matter whether you use chemical or organic fertilizers. Either way, you shouldn't use the spreader settings to determine the application. There are too many variables. I always calculate how much fertilizer (or seed) I need and adjust the spreader settings based on how much lawn I'm covering versus how much I should be covering.

I also try to make multiple passes at half the rate so that if I misjudge, every spot gets some, but some spots get more.

I'm assuming this is the fertilizer you applied.

I'm also assuming that you didn't really apply 2.5 tons of it on your lawn. The biggest bag they carry is a 50 lb bag, so I'm going to assume that's the one you used.

I could be wrong, but I think that since they have 7% water soluble nitrogen, even 50 lbs could cause burning in your situation.

You said the front lawn is slightly smaller than the back, and you have 10k sq ft total and you ran out after fertilizing half the front lawn.

Since you say "a bit" smaller, I'll assume the front is 5000 sq ft, so you applied the bag to 2500 sq ft. If the bag was a 50 lb bag, you applied about 1.4 lbs of water soluble N per 1k sq ft. That's high, and may cause burning, but it may not be high enough to burn. If the front lawn is significantly less than 5k sq ft, you will be more likely to have burning.

If you didn't mistype in the original post, and you really applied 5,000 lbs of this fertilizer to 2500 sq ft, I don't think anything will grow there for at least a year.

He probably meant a bag for 5,000 square feet, not a 5,000 pound bag. If so, then it was applied at slightly more than twice the recommended rate.

"There is only one organic fertilizer that will burn that I am aware of. That is blood meal applied too heavily."

Uncomposted poultry manure can also burn. I had access to uncomposted poultry manure many years ago and saw it burn when it was over applied.

I guess I don't think of uncomposted manure from any animal as a fertilizer. But it is probably in popular use, so I should keep it in mind.

If I read the original post correctly, he had covered 1/4 of the area with 1/2 of the fertilizer. He realized something was wrong and posted here before making it worse.

I got the impression he used 2 bags on half the lawn. Not clear about that.

When I used to use a spreader I made multiple passes, too. I would open the Scott's drop spreader all the way and it still took two passes.

Flowers--Can you clarify some of the questions that have come up?

Which product did you buy? How much did you apply?

From the various interpretations of what you posted, you're somewhere between a slight over application that won't be noticed to a toxic dump.