m0useanswered grow question 2 years ago Odd, spring water is not normally 0.00EC may want to check the EC monitor to see if its working right.
Spring water normally has mineral content of magnesium, potassium, calcium, sodium, and other trace minerals, maybe it is distilled or RO water??
Any who despite that first hiccup. it will all depend what your growing them in, soil, peat, coir and if its been fortified. Beware some things called potting soil mixes are not truly soil and are comprised of peat mostly. Mixes tend to be fortified for the first 2 weeks and won't need anything.
I would check your mediums mix and confirm if it is fortified with any slow release or regular fertilizers before feeding more. Then if it is wait a bit, and if it is not, feed them a low amount.
Just remember autos do not like strong feeds and its best to use 1/2 to 1/4 the recommended dose or make up the feed as per the label and then dilute it down with more water till you hit your desired EC if using liquid nutrients and adjust the PH. Dry amendments are a bit easier and can use 1/2 to 3/4 strength with PH'd water.
Good Luck!