We have tried a few containers for strawberries, (A) Timber (painted OSB sheet and polythene lined ) box raised up 24 " on 2"x2" legs, box was 8' by 2' by 10" worked well , plants near each side so fruits hang over. Pros.. Bit expensive,( you could recycle scrap timber ) , easy to water (lots) and keep clear of pests, keeps going for 3 years or more ( change plants after 3 years ) . Cons, (400ltr) loads of compost required , liable to attack by vine weevil, and in our case squirrels. (B) Strawberry grow bags on raised timber slats 6 /8 plants per bag, in a netted fruit cage Pros. easy to access , and protect, fruited well , Cons, only good for one year , hard to keep water right , ants ! .late frost will cause problems so need protection. ( C) as (B) but the grow bags sit in gravel trays to aid watering Cons, heavy rain and they swim . Our next years plan ... timber boxes 9" x 9" by 6 or 8 feet ,with drainage holes , up on posts 3' where we had the grow bags, a length 15mm plastic of water pipe with holes runs along the top to assist watering.... strawberries seem to fruit better if stressed a little, soil wise, too much you seem to get leaves , but not much flowering.