Since the 70s I have sprouted my avocado pits. On occasion I have managed to have beautiful plants as large as 48" high. Unfortunately, due to my gypsy tendencies, I have always given the plants away when I moved, and eventually gotten around to sprouting a new one. Well, last month, upon finishing a BLAT Kit® I brought to work (Bacon, Lettuce, Avocado & Tomato in a bag with 4 slices of bread, assembled at lunch to keep the sammich from being soggy), I decided it was time to try sprouting the pit again. Well, I just threw it out, slimy and unsprouted. Now that I look back on it, I don’t think I’ve successfully sprouted a damn avocado pit in years. I’ve tried leaving it in the dark, leaving it in room light, leaving it in the sun, poking with toothpicks to suspend in water and constructing an elaborate harness from paper clips to suspend the pit in water without piercing the pit itself. No luck. No sprout. The only thing poking out of the bottom of the pit is the tiny tuft that was poking out of one pit that came from an avocado that was a little past its prime. Being a natural cynic, I’m inclined to suspect that they’ve treated the fruit with some heinous chemical that has stunted the avocado’s natural sprouting ability. Is it just me, or is there some cosmic shift that happened that I’m not aware of that is hampering my ability to get a free avocado plant?
I never could get the hang of the water method.
I’ve had good results by finding a good fertile, sunny spot in the flower bed and planting the pit there after frost danger. By fall it’s usually 10 inches high or so, and I dig it up and pot it to bring inside.
Gee, thanks, Myron. I was starting to get a complex about this. 
Barring any unlikely success with the water method, I’ll try this in the spring. I’m really hoping we’ll be in a new house of our own by spring, and this would be a fine garden project to start with.
Would it not sprout in a pot in the sun, though?
I’m suspecting the same thing.
It’s probably been about 5 or 6 years since I last managed to sprout myself an avocado plant, and that one seems to have been an anomaly (the pit had already split and had a mini-sprout poking out when I cracked open the avocado).
My ex-BF killed that particular plant when he forgot to water it while I was on vacation… I wasn’t too happy, but I’ll be even unhappier if it turns out that was destined to be my last avocado plant ever. 
I just sprouted one a couple of years ago, but a surprise frost killed it.
I’ve never not been able to grow one, it’s just getting around to doing it that I have a hard time with. Maybe this spring?
How about pits from organic avocado’s?
The last paragraph in the answer here is probably the answer to your question.
I sprout 'em all the time. I just poke 'em in a pot of soil, water 'em, put 'em in a sunny spot and ignore 'em for a few months. They eventually come up. “Eventually” being the key word, here. It’s easy to decide they’re just not going to sprout and throw them out too soon. It takes a while.
I knew that chemicals were the culprit!
I seem to recall that in one of his old essays, Stephen Jat Gould wrote that the reason Avocado pits are so huge is that they were designed to be eaten and passed through the digestive tract of some seriously large herbivores, like Giant Sloths or Glyptodonts, that have since gone extinct. The seeds had to be large and have a thick coat to survive the passage, because they’d be seriously abraded along the way.
The problem is that the big herbivores aren’t around anymore, but the avocados still have large pits with thick coats. This makes it hard to sprout. The solution, he said, was to abrade down the coating on the pit so that the sprout could break through.
So singular1 just swallow the pit whole and poop in the garden!
Only if you’re a Megatherium or a Glyptodont.
Me, I’d rather use a file.
Actually, I’d rather use nothing. I don’t like avocados.
Not liking avocados is a sin. You will surely burn in hell and then all your avocados are us! Yum. 
I just go out in the yard every summer and get fresh ones from the avacado tree. The benefits of living in Florida.
So the two theories are: (1) Chemical treatments are keeping them from sprouting in the first place, or (2) the covering of the pit is too thick for the sprout to get through. The latter doesn’t seem likely to me, as I doubt the coverings have gotten thicker in the last few decades.
If the thick-covering theory is correct, you should be able to cut open a non-sprouting pit and see some growth going on inside it. singular1, have you tried this? That would at least let you know if it’s trying to grow.
(jtgain, I’m a Florida native. My mother used to take me to farmer’s markets and we’d get avocados the size of huge grapefruits. Mmm.)
I don’t like avacado’s either, and you can’t guacamakeme like them.
But I remember my Mom and all her friends sprouting evilcados in glasses of water.
A fruit that’s greasy? :pukey)
If you plant it in a pile of shit, compost, and sand, after sprouting you should have no problem. Sprouting an Avocado Seed | Horticulture and Home Pest News
I did one like my mother told me for date seeds - get some very absorbent, loamy compost, put it in a big ziplock bag and wet it fairly well (sqeeze any excess water out but get it all very wet) then bury the seeds in it, chuck it in a dark cupboard and forget it.
The avocado was put in the bag in May and completely forgotten until mid-august when I found it looking for something else! It had big tangly roots and a pale shoot. Took it into the light and it grew an inch a day for a while!
The crisis point for me comes when the pit has lost all its nutrients and is hollow or withered. Then is the plant going to like what you give it or is it going to die, leaf by leaf? I found some general plant food sticks that this one seems to like and it is now three years old. It likes a very sunny spot.
The date pips were great fun - I got dozens of plantlets and the oldest one was chucked out nearly fifteen years later when it had a spread of fronds that were about three feet long and a foot across each. Unfortunately they were razor sharp and when it finally outgrew the last place in the house that would accommodate it (the bathroom, so I got tired of my butt being assaulted as I brushed my teeth!) it had to go. I’d love to have another date palm but haven’t seen dates on sale EVER in Japan!