Sulfer(S) is one of the secondary nutrients and is also an immobile element. It contributes to root growth, plants building of proteins, and chlorophyll production. Sulfer works in the plant slowly and warmer ambient temperatures make it harder to absorb for your plants.
The first signs of a deficiency are pale leaves, looking like a Nitrogen(N) problem but being an immobile element it shows up on the newer young leaves instead. It also starts at the back of the leaf and moves forward. The stems grow in thin, hard, and spindly. Growth remains slow with the leaves getting brittle and staying narrower than what is normal. The buds on the top of the plants can even die off if not taken care of. Too much Sulfer(S) can also cause your entire plant to be small along with the size of your leaves.
Sulfur(S) also needs a good PH in the water mix and can be locked out at less that 5.5 and more than 9 when growing in soil. It also won't absord into your plant at less than a 5.5 and higher than a 9 in hydro and soil less as well.
A quick fix for this is to mix 1 teaspoon of epsom salts (yes epsom salts have sulfur in it) per gallon of water until condition improves.
Driving to one of our San Luis County grow stores will put you in touch with one of our resident experts as well as putting you right there to get the product too.
Nick at Garden All Year recommends that his customers pick up some Super Bat budswel. It's a great additive for Sulfur(S) as well as many other micro nutrients. He also likes Azemite for this because if your soils PH is a little high it can also bring it right down. Dyna-Gro also makes their foliar spray which can supply your plants with all their micro nutrients including Sulfur(S).
In San Luis Obispo at the Healthy Harvest store they recommend getting one of their fine micro-nutrient products which have small amounts of all the micros your plant could need including Sulfur(S). In particular they like the CNS17 from Botanicare. It works out real nice that as long as your plants aren't flowering it works as an excellent foliar feed so the results will show up much quicker. You can also use this as an additive to your water which works good too.