Whether it is in light or not is unlikely to make a difference in sweetness. If they do not eventually sweeten up--and they now look ripe--and they do this next year as well, I would follow Drew's recommendation and find mulberry trees whose fruit you do like and graft onto your present tree. It is possible that the tree will sweeten up over 4 years in the ground or so, but it is more likely a bum tree.

I have Monty on Mazzard and its been fine. That said I also have three cherries on Gisela 5 and they are all doing fine eight years later. I have found all cherries pretty easy to grow; maybe I have just been lucky. Cracking fruit on the sweets has been the main problem, and bacterial cankers have occasionally required major prune jobs. I just lost a Bing graft a few weeks ago to canker, my first variety lost to canker.

You will find it much easier to grow sour cherries than sweet ones. For one thing, sour cherries are self-fertile; only one tree is needed to get fruit. With sweet cherries, this depends on the variety; some require you plant another variety to get fruit. But this is really a minor issue. The main one is that sweet cherries in Maryland are a lot of work and will need spraying. For example, my neighbor's Stella sweet cherry this year set an enormous crop. How many cherries did he get to eat? None. Rot set in and every single cherry was lost to it. This is a major problem in our hot and humid climate. They are also susceptible to cracking after rain. Sweet cherries also grow into larger trees, making it harder to keep the birds off -- if you avoid rot, you still have to deal with birds. My recommendation would be to go with sour cherries. I have two: Montmorency and North Star. There are quite a few discussions of these and sweet cherries on Garden Web -- search for Jellyman's comments on cherries. My limited experience is this: Montmorency, third year, nice crop of sour cherries, very little rot damage, since cherries are not tightly clustered. Small tree could be netted to keep birds off. North Star: second year, a few cherries; a naturally dwarfed tree. But North Star is susceptible to Canker, a bacterial disease. Mine has it, and there are lots of posts by people whose North Stars also have it. So given my limited experience, I'd vote for Montmorency. I bought mine from Burnt Ridge Nursery; it is on a Colt rootstock and has done well for me. I would not grow North Star again. You can eat sour cherries out of hand, if you let them get fully ripe and don't mind some tartness along with sweetness. But they are really useful for pies (make fantastic pies), you can dry them as snacks and to put into baked goods or even salads; and you can make wine out of them. Regarding nurseries, I guess Gurney's is ok. I prefer to buy from nurseries that tell you more about the trees, especially the rootstocks (the root portion of the tree the named variety is grafted onto), or will do so if you email them. Rootstocks can make a difference and you might want to do a little research on this on line. Go to www.nafex.org and scroll down to their list of nurseries, and do a little exploring there. I've often used Hidden Springs nursery out of Tennessee, small and reputable and experienced with our kind of climate. Late fall would be a good time to plant trees in Maryland. Here is a link that might be useful: nafex nursery list

Sorry, you are disappointed with your cherries. The Earthbox is a great product so it may be just your variety choices as mentioned. I also find with some tomatoes the flavors improve as the days pass. While yellow pear may have some admirers there are many who find the taste bland and the texture yukky--I am in the latter camp. Can't imagine it being tart though--maybe it is just the first few off the vine. Hopefully you will like them better given a little bit more time. A great SWEET red cherry available most everywhere is Sweet Million or Sweet 100--taste like candy (Psss, don't tell anyone but I like them better than SunGold). Hopefully you got that one and will like them more and more as they ripen. Not sure which other type of cherry you may have purchased?? I have read that tomato plants need full sun to develop maximum sweetness--hope you have those conditions.