Are you wiping them down with water? I don't know, but I did learn one year to make sure that I used very very little water on my cloth. I had Large Red Cherrys that were wonderful UNTIL I wiped them down to clean them. Cloth too wet and I won't do that again.

I have had very little problems with splitting, but then I'm dry farming and I pick at first blush (esp. if rain is predicted, then I grab everything showing the slightest hint of color) and let ripen in the house. I did have 1 ripe Black Krim split at/on the way to market on Friday but it was pretty ripe and I understand they're very delicate. I was worried I wasn't even going to be able to get them to market this year (first year growing). No problems at all with the Cherokee Purple.

Are they splitting during transport (even packed single) or just sitting there waiting for CSA pickup? How warm is the area they are held in?

I'm having problems with stems poking holes in neighboring tomatoes when I pack them all in a box, even though I try to place any with stems still attached with the stems down. I'm not washing them at all before market - mulched pretty well and other than the odd bird poo (which I do wipe off with a damp paper towel) they haven't needed it. I just tell people to wash them before eating, pack them single to a paper lunch bag upon purchase (stem side down), and tell them to handle the BKs very carefully.

In regards to the stem pokes, just break of all stems. That will fix your problems. I dont know why for sure, but we always have problems with shelf life and cracking in the fall.

Jay

Since I'm picking before they're fully ripe, sometimes the stems come along. I'm afraid of pulling it too much and cracking around the calyx. But I will try pulling them off after they ripen and before I pack them for market.

Only had that 1 BK split, but had some split cherries when I got to market. I think they got too hot in the truck (put the bins in the toolbox and left it open til we were ready to leave, but even a short 7-mile drive on a hot day was enough, and/or it was the movement).

First time ever growing heirlooms and it has been terrible. Production has been decent, taste great, but I am almost thinking that they are too delicate to bother with. Other local market growers I talk to find them very frustrating. I tried picking them a little early but that is not worth bothering with because there are too many better things that could be done with the time and energy.

Hybrids that are much more manageable(for me) will make enough money. Next year, for standard tomatoes I am planting more viva Italia roma and more Ace VF55. The handle better and produce well and pick well from the tomato cages I have. The Viva Italia are making around 100pounds & up, per 5 foot bush plant. With primarily these two, and some cherries, it seems I am the "go to" guy for tomatoes at one of my two markets. I'll plant some heirlooms next year, but won't be counting on them at all...more of an added interest thing.

White Tomasols have gotten people to stop an look ...and then they buy the other "common" tomatoes. For the rest of the year I am selling whatever I have, "Mix and match" all for the same price...except for the Marzano's which are higher.

I think you gotta experiment with varieties, not buy the popular, well-known ones. I have had BER and cracking of all kinds and have had watering problems for some weeks. I never let them fully ripen on the plant except for some cherries that get missed. Right now all the Sungolds (the only hybrid I grow) are splitting. They start great and then the skins become a problem.
I have no splitting on the smaller, cocktail size varieties.
Some of the best varieties I grow are Brandywine Red, McClintock's Big, Stupice, San Marzano, Japanese Black Trifele and JD's Special C Tex (huge production but it is cracking badly now.) My other favorites are accidental crosses from seed trades. I no longer grow Sudduth's Brandywine or Cherokee Purple.

Hmm, that's funny, Sudduth is known to be more adapted to cooler zones, and it has done great for me this year. I only have the 1 CP and it hasn't been a big producer, but no problems with cracking and the fruit is a nicer shape than the BKs (horribly lumpy, fused blossoms and catfacing). I want to try BK seed from somewhere other than Burpee next year, but will definitely buy some CP seed too, and decide after 1 more year which one to grow in the future.

Sudduth is definitely a keeper for me, even if it's just for personal consumption (it sells pretty well, so far is just about neck and neck with BK). It's my dad's new favorite (though my mom still prefers "regular" tomatoes).

You need to pick the heirlooms a little greener than the hybrids, and handle them like they were eggs. take your boxes right out in the field, pick a couple and pack them right up. Put a blanket over the boxes on the wagon so that they don't get too hot.Don't use pick baskets unless you only put them in there single layer only. You can get splits if you pile them up and bruises too.
If the stems are really persistant, take a pair of snip type pruners and cut them off as short as possible. Then when you take them to the market, put heirlooms on your sign, but leave the tomatoes in the box and don't let people handle them. when people ask you which ones are heirlooms, whip the box out and tell them that they are delicate, soft,bruise easily and can't withstand handling. But also tell them how special they are, and how much work it is to get them there in good shape, and how good they taste! And don't let people finger them around and ruin your tomatoes. You will naturally have a lot of splits in heirlooms no matter what you do. but picking them greener helps a lot, and if you hear rain is forecast, get out there and get them picked before it rains.
Also, get a list started of people who want canning or juicing tomatoes, and when you get some splits, start calling down that list real quick and explain that you have some delicate heirlooms that are very perishable but delicious and do they want to do some canning/juicing NOW--today...that usually works for me. be sure they know that this is something that they can't get just anywhere or anytime, put a little urgency in there.

Thanks for your pointers,Minnie abd Sandy. I've been mulling the question over since reading your posts.
After having a good weekend with them this week,
I may not give up on them after all. I've seen some nice varieties around. Someone gave me a beautiful orange one that had the beautiful color of a persimmon, tasted great and had good handling qualities too. Might just have to plant them where I can't accidentally flood them, like I did several times this year...and pick them as you say, earlier....and remove the stems... spread them apart so rats are easier to get....etc.

I found that the ones that I pruned the first three suckers gave more consistently large tomatoes too. That was another problem, though lots of people do buy the small ones, I think they will pay more for big.