Am I using too much nitrogen?

[Errol]

I grow a number of plants (tomatoes, cucumbers, capsicum, strawberries, beans, leeks, beetroot and even carrots) in laundry buckets, in the same recirculating greenhouse hydroponic system. The pre-mixed dry nutrient I use is Peters Professional Hydrosol, containing 6N+36P+18K+3Mg and I've also been adding an equal quantity of calcium nitrate (19.6N+15.5Ca) plus a little Fe. I run with an EC reading of 2.0 which keeps the plants generally happy, although the tomato buckets do get an occasional individual nutrient bonus of 3.0 closer to picking time. The local water supply has a ph of around 7.0 which the plants seem to handle well enough (maybe I should adjust this?). You can probably tell from all this that I'm not an 'exact' hydroponic gardener and that I try to grow a range of plants using a 'median' EC and ph.

I've generally achieved quite acceptable results for some seven years now, but one problem needs fixing - the plants produce too much growth and have large root systems. Strawberries in particular are far too leafy, resulting in aphid, then wasp invasions later in the season.

I'm thinking of cutting back the nitrogen to moderate excessive vegetative growth. Can readers suggest whether I'm on the right track or just heading for trouble? Any advice on plant nutrition would be welcome. Thanks.