Plants small but bushy? PICS

Hi guys,

This is my first time growing and I'm not sure if my plants are normal. I am growing 4 plants under a 400w MH in a reflective box with a 200mm extraction fan. They are growing in Potting Mix (4 month supply of nutrients) and receive about 100ml/day each. They were planted 22 days ago and their current height is 7cm (2.75 inches) and are now producing heaps of leaves while remaining short. Is this normal?

how far away is the 400Wmh

It is 80cm (31.5inches) from the tips of the plants

You shouldn't be watering them everyday unless they need it. Are you checking to make sure the soil has dried out a bit before watering again?

Oh okay, what would you recommend as a good watering interval? The soil is usually bone dry before the next watering.

Most people use one of two methods:

1.) Finger the pot - Put your finger an inch or so down into the soil. If it feels dry/slightly damp, it's due for a watering. If it's still wet/moist, it's still wicking up all the water you gave it previously.
Or/And (I use these methods in combination to make sure)
2.) Lift the pot - Before you water, lift the pot and get a feel for how heavy it is. Water your plant thoroughly. Pick up the pot, get a feeling for how heavy it is now after watering; it will be much heavier. Now next time you go to water, pick up the pot. Does it feel as light as when you know it was dry?

Another tell-tale sign that your plants desperately need water is severe drooping of leaves. Oddly enough, this will also sometimes happen right after you water. So if your leaves aren't drooping, and they begin to droop after watering; no worries.