I have a large container garden. Some of the containers seem to do poorly no matter what I plant in them. I'm constantly battling ants who make nests in all my pots. I have one oak barrel that doesn't seem to do well no matter what I plant in it. I have problems with my containers in south and west exposures. I think the containers heat up. Any suggestions. I've tried borax ant bait and it seems to keep them from invading the house but the potted plants just keep getting it. I should try tangle foot but it gets so gross looking around my pretty ceramic pots and I don't know if it would work on an oak barrel with cracks in it. I'm really getting frustrated. I have the pots on gravel. The gophers here are so bad i use pots so I don;t have to buy a gopher basket for every single plant. we're gonna get a sink hole soon due to our over abundance of subterranean creatures!!!
ants nesting in oak barrels and pots, ew!
Have you tried pot feet? Ants like to get between the pot and whatever it's sitting on. That said, I have so many planters that I don't have feet under all of them. Some years the ants just seem to be worse than others.
I'd also look into other things besides the ants...I've had ants take up residence in a number of my pots and I've never noticed any ill effects on the plants so that makes me think there might be something else going on. With the oak barrel I doubt if it's heating up that much, unless it's a really tiny barrel there is enough soil volume in there and the barrels are usually light enough colored and don't conduct heat that much. I have things in 1 and 5 gallon black plastic pots on my west facing deck and my summers are hotter than yours and as long as I keep them watered I haven't had any problems and I'd be surprised if your oak barrel was a worse situation in terms of heating up (although some plants are undoubtedly more sensitive to things like that than others) If the barrel is too big for your plants that could cause problems though--having a container that's a lot larger than the plants in it can make it very easy to overwater things.
The other problem I've had with containers which would be worth checking into is how thoroughly you're watering when you do water...if the soil gets dried out, often the next time you go to water it'll run right through and out the drain holes, then you see that and think it's had enough water but what's really happened is the water has just found a few channels down through the soil, but the majority of the pot is still bone dry. So you need to give it a thorough soaking, pour water through several times to make sure you've got the soil wet all the way through. I have to say when I have containers that are struggling in the summertime, 9 times out of 10 that has been the reason and as soon as I start watering them thoroughly they do much better.
i've had the problem with not being able to wet all the soil before in this exact container. I think you might be right. This maybe happening again. The ants have made little tunnels down the edges of the soil, they are also i think giving the plants aphids. I think its a combination of all the problems you mentioned. I use this barrel to grow veggies in it may be too deep. it's pretty big.
ecrane what potting mix do you use? I feel like the kind i use can some times form a water resistant surface. it is "gardener and bloom" organic potting soil.
the other thing is - its been raining so i don't think its to dry? but i'll go check.
It's been warm enough over here recently that my smaller containers have been getting dried out and needing to be watered but my larger containers still aren't needing anything. I was assuming most of your issues were happening during hotter summer weather which is why I thought of the watering thing--if you've got plants that are unhappy now then there's probably something else going on.
I use Miracle Gro potting mix just because it's easy to find--I usually buy the organic one but if they're out of stock and I need some then I'll get the regular kind. If it gets really dry then it does tend to resist re-wetting, that's why you have to really soak it. Most potting mixes will behave that way so it doesn't surprise me that yours does the same thing.