Foliar feed for struggling tomatoes

I made the mistake of going to visit family out of county and had no choice but to leave my tomatoes out in the mini-polytunnel with the front open and sitting in saucers of water - I know, not ideal, next year I will start them later after the compulsory family rounds.

Now the my early toms are struggling - browned off leaves, purple looking leaves but the new leaves are looking rich and green and I think they are going to pick up.

The pots are still well watered and the struggling plants are not taking up so much water, but I think they could benefit from a weak feed. My question: can I expect my plants to benefit from a weak multi-purpose foliar feed administered by a fine mister? Or should I choose a tomato feed? It's foliar growth I'm trying to encourage at this stage.

Received wisdon is that you use one type of fertiliser for growth (N) and another for fruiting (K). But my chilli food suggests just increasing the dose for fruitng:

For young plants or seedlings mix 5ml per litre of clean water once a week or more frequently if plants look pale. The vegetative stage of growth varies from plant to plant depending on species, cultivar and cultural techniques. The dose of 5ml per litre of water should be maintained until the first sign of blossom. After the onset of flowering increase dose to 10ml per litre of water and supply to plants weekly

Obviously they want you to use their fertilizer. But I guess any feed is better than no feed.

Many thanks. I'll use a half strength (N) foliar spray as I can't water the pots yet.

I've used Maxicrop general liquid feed watered in when needed as a boost, but as a foliar spray which it says you can do as a pick-me-up. If you mist over, then it won't run off the leaves nor will it make the compost even more wet.

I find that a foliar feed of home-made comfrey tea works well on just about everything:)