For the past few months, I have had zero success in getting any seed from store bought citrus to actually germinate. I've been trying specifically for Key Limes. I'm ready to try organically certified citrus, but the local availability of organic is very limited

This isn't just limited to the Key Limes, though...I've tried several dozen seeds from different citrus (some Valencia oranges, the Key Limes, various lemons and others) and fruit from a couple of different stores and packers.

I'm wondering if anyone else has noticed this as a problem?

I've never had this problem. I've successfully germinated Valencia Orange, Clementine, Mandarin, Grapefruit, Lemon, Nagami Kumquat from store bought fruit. Could you describe your germination method?

And it has been primarily the last 6 to 9 months...

Here goes...

Take the seeds, fresh from the fruit, rinse well to wash off any juice, dry on a paper towel (just so they aren't slipping around all over the place from being wet). Insert seeds into seed starting mix (same as I use for everything else a homemade mix of well composted wood chips, coir/peat moss, perlite) in either individual small pots or inserts for flats, usually 6x6. Then depending on when it is, either with the rest of the stuff I'm starting from seed, out to my grow room or set on the shelf over my kitchen sink. Basically, the same methods I've always used., from when I was able to sprout them (I cooked my last successful bast last spring, along with a flat of cabbages by forgetting to vent the hoophosuse on a bright, sunny day).

The last batch was a dozen lemon seeds that, after nearly three months, showed now signs of germination...in fact several of them had gone 'mushy'

Try some bottom heat.

I agree with Laaz, bottom heat helps germination a great deal. You could also try omitting the composted wood chips from your soil medium, they might be encouraging the seeds to rot. I use a sterile mix of 1 part sharp sand and 4 parts coir. You could use the perlite in place of the sharp sand. Covering the top of your pots or seed trays with clingfilm or a plastic bag helps by stopping the medium from drying out, until the seeds sprout. You could also use the baggie method which has worked for me many times:

http://www.instructables.com/id/Seed-Starting-with-the-%22Baggie-Method.%22/

Good luck with future seeds!

If you remove the testa (the outer hard yellow covering) and germinate the seed in a medium heated to 86F (bottom heat) germination should occur in approximately 10 days. Without removing the testa, but still suppling 86F bottom heat germination should be in approximately 16-24 days. - Millet (693-)

Well, they have tangerines on sale at the store, this week, (and we've already nearly gone through one 3 lb bag) so I've got some seeds to try.

I had some issues with early germination myself, I believe the problem I had was not having enough heat. Not sure if you are trying to germinate on a professional/industrial scale.

If you just want 30-40 seeds here is the method I have used with a lot of success.

First off as others have mentioned peeling off the outer membrane helps the seeds germinate a LOT faster, I soak mine for about 24 hours, then dry them off with a paper towel and proceed to take off just the outermost part of the seed.

I took 4 paper towels and ran them under the faucet. I squeezed out the excess water and put 3 paper towels down on top of each other. Then place your recently peeled seeds on top of the 3 paper towels, somewhat scattering them out so they are not piled together. Lay the 4th paper towel on top of the seeds and put the whole thing inside a gallon plastic ziplock/freezer back but do NOT fully seal the bag, maybe close it half way if your house is really dry.

At this point they need to be kept warm, some people put them in a greenhouse, some use a germination heating pad. I put mine on top of my cable box, it is a cable/DVR box so it is about the size of an old VCR and it is always on so it stays warm to the touch. Try to find a place like that in your house that is warm but not hot, on top of an older model refrigerator also works.

Every 1-2 days open the bag just a little and use a spray bottle to keep the paper towels damp, wait a few days BE PATIENT! and you will be rewarded with some seeds with roots, and if you leave them longer small shoots, and if you forget about them for a week a mini forest

Take all of that with a giant grain of salt as I am very much an armature gardener and there are people here with much more knowledge and experience, the above is just what worked for me.

Good luck

Another thing that came to mind if you use the method I described before is if you leave the seeds for a while the roots will try to bind to the paper towel, which I noticed my 4th round of germination. So I would recommend putting them in soil before they develop to much. Again take all of that with a grain of salt as I am by no means an expert, just a guy who got lucky with germination.

I have used this method for germinating many other things, so that's what I did with the current batch of seeds.

I have found, in the past, that it isn't a problem if the roots do grow into the paper towel...just pull it apart to separate the seedlings and plant. The paper towel will quickly disintegrate and become part of the potting mix.

Yea a little paper towel is most likely not going to hurt anything, it just bugged me a little

Well, it has been several weeks now and I am glad to report some success. The lemon seeds I tried have sprouted (finally).

Now to get some Key Limes (none of the stores around here have any at the moment).

Millet, how do you safely remove the testa without damaging the seed? (They're slippery little buggers.)

I just use my finger nails. I pinch/break off the tip, and then peel back the testa. I damage perhaps 1 seed in 20. A citrus seed germinated at temperatures between 86 - 90F with the testa removed normally germinates in 10 days. If you let the seed dry for 20 or 30 minutes the seed's surface will dry and will not be slippery. I always germinate them in regular potting soil of some type. In the Brazilian commercial citrus industry 100 percent of citrus seeds have the testa removed before planting, and that is of course tens of thousand seeds. - Millet (670-)

Thanks, Millet. Have this one and only very fat little Dekopan seed, so I want to try not to damage it if I can. Have a seed heat pad I can use, and it's going in a sunny window, so it should germinate for me if I can take care to remove the testa. I happen to have some seed starting medium and I'll zap it in the microwave to make sure it's sterile. Last time I did this, I think I was 8 And that was with a brown paper towel and a baggie. Or, maybe it was wax paper, since I don't think we had plastic baggies back in the 60's!!