How much food is too much food?

bobvisaaAugust 28, 2013

I recently read that feeding red worms too much would kill them. Since I have an abundant amount of horse and cow manure to feed my worms, how do I know how much to feed them without overfeeding them.

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Can't get much better of an answer than what sbryce posted at

I'm more of a keep jamming the food into the bin until they all die and the next time use a bit less food kind of a person. Eventually either the worms eat faster or I get smarter.

    Bookmark   August 28, 2013 at 7:57AM
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In the interest of redundancy, here it is again:

With horse manure it is almost impossible to give them too much. Let the cow manure pre-compost, and it is almost impossible to give them too much.

When we talk about too much food, we are usually talking about kitchen scraps. Too much food in the form of kitchen scraps will create a pretty yucky environment. The moisture in the food will cause the bin to go anaerobic, and the high nitrogen will throw off the bin's environment.

Whatever you feed them, worms will consume about half their body weight each day. Under good conditions, they will eat their own body weight each day. Too much food is simply more than they can eat.

Another factor that determines over feeding is the tendency of the food to heat up as it is breaking down. Both horse and cow manure can heat up quite a bit. If they have been aged to the point where they will no longer heat up, you won't have this problem.

Any food you put in the bin should be totally consumed by the worms in about a week. Additional food can be added before that to give it a chance to break down before the worms attack it. You are feeding too much if it is not all consumed within a week.

So our rule of thumb is to add about 1/2 pound of food for each pound of worms per day. You don't need to feed every day. You could feed 2 pounds of food for each pound of worms every fourth day. Then watch to see how fast the worms eat it and adjust the amount you feed accordingly.

Aged horse manure is an ideal worm food. I would add about a pound of horse manure for each pound of worms and see how fast they eat it. You won't need bedding. Your only concern is for over heating. With cow manure, you will need some bedding. I would add about a pound of aged cow manure plus bedding for each pound of worms and see how fast they eat it.

Feeding is as much an art as it is a science. In time you will figure it out. If you are feeding aged horse manure, or even small amounts of fresh manure, it is hard to make any big mistakes. You could fill your entire bin with aged horse manure, and your worms will be very happy.

Weighing food isn't practical, and weighing your worms is nearly impossible, so add no more than an inch of aged manure over the top of the bin and see what happens. If the manure is still fresh, only cover half of the bin surface. That way, if the manure gets hot, the worms can escape to the other side of the bin. In a few days it will cool off, and the worms will be all over it. Really. Worms devouring horse manure is a sight to see.

Your bin will be less than 8 inches deep, so this is what I would do. If the manure is well aged, fill the entire bin with horse manure, and feed enough to keep the depth between 6 and 8 inches. If you are feeding cow manure, you will need a bedding source as well. If there is any question as to whether the manure has aged enough, fill the bin with some form of bedding, and feed enough manure on the top to keep the depth between 6 and 8 inches, only feeding half of the bin surface at a time.

If the manure is fresh, you could start with a mixture of manure and bedding and let the bin sit for a couple of weeks before adding worms. After a couple of weeks, turn the whole thing and make sure it does not heat up. If it does heat up, wait another week and try again.

This is getting long. Time to post it. If I missed anything, someone else will fill in the holes.

    Bookmark   August 28, 2013 at 10:07AM
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I'll just add that with food scraps too much food is subjective. In general, we think of more food than the worms can consume in a week, but that can vary, given the type of food.

Whole corn cobs will take months to be consumed, but sticking one or two in the bin won't be a problem. Grind them up, and they will be mostly gone in a week. I have likewise put whole apples, lettuce, potatoes and tomatoes in my bin with no problems.

It takes very little starchy food too be too much. I almost killed my worms feeding them dry rice. And though the worms won't complain, any amount of broccoli in the bin will make you think you overfed them until it is gone.

It has more to do with conditions in the bin than with the total amount of food. What you don't want is a bunch of mushy muck in the bin that the worms can't eat fairly quickly. You want mushy muck. That is what the worms eat. But you don't want so much of it that anaerobic bacteria move in faster than the worms do.

    Bookmark   August 28, 2013 at 10:17AM
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It's kinda like feeding your kids. Make them eat what's on their plate. When the previous feeding is seemingly gone, feed them again.

I say "seemingly" because after that little chunk of squash or decomposing cabbage has vanished, there remain teeny tiny little bits of that stuff that wormies come back for.

Guess I'm saying that some folks think the herd is hungry because no visible bits of foodstuff can be seen by our pitiful human eyeballs. Hence overfeeding.

Worms take advantage of every opportunity we throw at them.


    Bookmark   August 28, 2013 at 10:26PM
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