like seamaiden said watch your plants, i find that if you use a doog quality soil you may not have to feed much. salts tend to build up in soil grows if you feed often, and the pH can change. some soils are highly fertilised and are quoted as lasting up to 6 weeks before you need to feed, be carefull with these though as they can harm young plants, i recently transplanted 6 seedlings into bigger pots and richer soils, the three that went into plagron batmix showed signs of overfertilization, crinkly leaves etc, the other three, went into westlands multi purpose with added john innes, this stuff fried the plants, the 3 in plagron recovered i budded them last week but have chopped them as they were males. the three in westlands shit i had to rinse all the soil away and re pot them, in b and q multipurpose,
they are now nine weeks old, and smaller than a seedling a planted two weeks ago, i would have scrapped them, but they are new genetics for me and i wanted a female to clone.
i find that if i use good soil i vedge for 3 to 4 weeks then put them on 12/12 they sometimes show a potassium deff at about 4th week of flower so i feed HALF STRENGTH
lucas with GH nutes. but if the plants look dark green and ok just water them. on soil be carefull with manufacturers recommendations for nute dilutions, you will be better giving plants no more than half strength, you do not want the nutes ec to be more than 0.850
that is about 424ppm @ 0.5 conversion. also if you can you should use dolomite lime in your soil at a rate of about 1 teaspoon per gallon of soil, this reduces the need to supplement calcium and magnesium later on, and stabilises the soil pH, when you water you want the water to be pH 6.5. forget about fixed feeding schedules on soil, do what seamaiden said and watch your plants. good luck with your grow. let us know how it works out.
