you can get special compost but I think its the feeding and watering thats very important,slow release fertiliser and water retaining gel can help if they are mixed with the compost on planting, I usually put a piece of plastic at the base of the basket before adding the compost

I agree with Pamg. I've grown a lot of hanging baskets over the years. I don't think there is any "Special" compost. The slow release fertilisers and water retaining gels are a must this helps the plants take water and food as required. Watering regular is a must in hotter temperatures as baskets should not dry out.Once plants have matured I would still feed at least once a week as the slow release fertiliser will not last the whole season.I know it can be more work but I have always had best results lining the wired baskets with moss.This can be bought in most garden centres but shop about as prices vary quite a lot. Also, don't be tempted to overfill the baskets . When planting up obviously plants are small and its all to easy to overfill then plants will struggle.Depending on variety of plants used always try deadheading withered flowers, this will promote longer and new growth.If you go away for a couple of days cut the bottom off a plastic container(Pop bottle) stick it in basket and fill with water. Hope this helps.

i use water retaining gel and slow release fertiliser too and everything seems to do well. i dont over stuff them either. they start off looking a bit sparse but fill out nicely.

Thanks so much for the tips I will try this summer. Have a great year.

Yes I agree, new compost to start with but regular feeding and watering, never let them dry out and regular dead heading, I dead head every day and its very quick then. When I start I screw up a small plastic bag in the bottom to hold some of the water, I also stand pots under my baskets and the water drips into them. Before I go away I completely dead head them and have a lovely show when I come back.