Agree - they (tomatillos) are not usually pruned. Doing so will substantially reduce your production. Do they have sucker branches that should be pruned? Is there a main stalk to keep clean? But for future reference, neither are tomato plants - pruned that is. ;) Pruning is OPTIONAL, not mandatory and depends on how you support them and what type they are. So called "sucker" branches do not have to be removed and believe it or not, many gardeners don't remove them, and stems do not have to be "kept clean". So if you are also growing tomatoes you might want to do some reading about pruning over on the growing tomatoes forum here. As to BER (blossom end rot) it's possible but it usually isn't a problem because they are a small fruited variety. Hopefully there are two plants because it takes more than one to pollinate effectively for the best production. If there was more than one in the pot as is often the case it would be best to separate them when planting but it may be too late for that now. Dave Here is a link that might be useful: How to Grow Tomatillos

lonmower - Like you I'm in a cool summer climate. We're in a clearing in the woods in western WA, so a bit cooler yet. Once the sun lowers in mid August we get even more dappled shade for part of the day from the tall trees. I have pruned before thinking it was the right thing to do. It wasn't worth the time or lower harvest plus when there is a hot spell you get sunscald like was said. I have pretty good air circulation, so that's not been a problem even with an intensively planted row. You could try pruning one plant & see what you notice. I either pruned or not, so can't really compare one plant to another. I just prefer to let the tomatoes grow like crazy in June hopefully blossoming & setting fruit into July. My goal is 5 trusses of fruit per plant. If I pruned them I would be removing chances of fruit. In a long season climate you could prune and still get a good harvest. I know my 5 trusses is meager, but a reasonable goal for my short season. I plant more plants to try to make up the difference and count every vine ripened tomato a blessing. I encourage the tomatoes to ripen by stopping watering in August & only water if plants wilt. I have lots of organic matter in my soil + mulch + soakers to water. Around Labor Day if not right before I cut any blossoms & small fruits. Once temps are below 50 degrees again I bring in all fruits to ripen inside because when it's cold like that they lose flavor and just rot. Below 50 degrees the garden becomes a refrigerator, which is good for fall & winter harvesting of cool weather vegetables, but not warm weather ones. Others in my area can keep them producing until frost especially with some protection after that 1st early light frost in October.

Did the OP mention anything about production per sq. foot? I don't think so. Sq. foot production may be of interest to you but it isn't of interest to many, if not most, gardeners. Production per plant is. f it does not appeal to you plant JUST one in 3' x 3" (=9 sf) I don't know where you are getting your measurements but assuming you mean that 3 feet x 3 feet (not inches) = 9 sq. feet is one spacing option you are right. That is because the average indeterminate tomato plant is at least 3-4' wide. But you can do the same test using any plant spacing you wish within reason and get the same results. And yes in a 3' x 6' bed I would probably plant only 3 (not 2) stagger-planted indeterminate varieties, caged and unpruned. And assuming we used the same varieties and provided the same growing conditions I would get 2 to 3x the production in both weight and numbers you will get from 6 plants in that same bed. You might get a few ripe fruit earlier and might get a few that are somewhat larger but your overall production in numbers and total weight will be much less than mine It is simple anatomy of a tomato plant as it grows. I can say that because I have done it in my own gardens many times. In over 50 years of raising tomatoes I have tried just about everything at least once if not more just to discover for myself what works best. One never knows unless they give it a real try. Otherwise it is just guessing. _____________ Macer - yes IMO you will need to prune them. A 3-4' wide plant just can't grow well in 1' of space. Personally, even though they are a foot tall I would be tempted to try to transplant a couple of them. Alternative - root cuttings off the center 2 and then snip the mother plants off at ground level and plant the 2 rooted cuttings with better spacing. Dave

You are going to have to experiment and see which approach works best for you in your growing situation, Sumilea because other than the "never prune determinates" bit you will never get a definitive answer or agreement - as all the many past discussions and debates here on this issue will prove. ;) The schools of thought on radical pruning vs. limited pruning vs. not pruning all have their diehard believers, their research, and their experiments to support their particular beliefs. All with equal validity because there are so many factors/variables involved - sun exposure, types of supports, air circulation, disease incidence, fertilization, size of container/garden bed, amount of time to work on the plants, soil composition, etc., etc. It is impossible for any to claim that this is the only way that works....tho some do try. ;) My question is if you don't prune for increased yield how bad will the size of the tomatoes effected? This claim that one needs to sacrifice one to get the other (yield vs. size) doesn't always hold true either so experiment and remember that size is predominately a matter of variety genetics. See if your pruned plants in your garden produce bigger or more fruit than the un-pruned ones do when all are subjected to the same growing conditions. is it better to have 1 or 2 suckers grow or just leave it to 1 stem Again, it depends on your growing situation and the form of supports you use. Try both and see which works best for you. That is how we all learned what works best for us. ;) Dave