could i use a hps light to veg or it's not good?

You can use hps just fine for veg, although mh (metal halide) is still recommended.

There are plenty of grow logs on here showing hps-usage during veg; perhaps you should check some out?

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Nutrient Deficiencies

so can you guys tell me the difference between them in the veg stage like which one will make them stretch or bushy?cant find grow log with hps

HPS does "stretch" more than an MH bulb but you can do an entire grow with nothing but HPS, I did for quite some time until I relized I had an auto switching ballast and all I had to do was change the bulb

MH stretches between nodes, HPS bushes between nodes, the HPS is better for short bushy rock nugs, and HPS is good for all stages. MH is a good mix to throw in on the HPS, say if you have dual hood, a 600 HPS and a 400 MH. To each their own though.MH does make airy nugs if thats all you use.