Lower wattage in a higher wattage ballast?

Hello everyone. Let me start by saying that I am not yet a grower, and though I have gathered a good deal of knowledge by lurking around these forums, I still have questions.

Anyway, getting to the point... my question!

Say, I acquired a 400w HPS ballast from a friend or vendor for cheap. Now, I am not going to be running a very large garden, and as such, I do not need a 400w bulb to keep my garden going. I figure, with the garden situation I have in mind, a 250w HPS bulb would be sufficient. My question is, is it safe to screw in a 250w bulb in the socket of a 400w lamp?

This scenario is purely fictitious and created solely for hypothetical purposes.

Any help would be greatly appreciated. Thanks!

It's asolutley safe, as long as you don't plug the ballast in.

The hps 400 bulb requires a much higher amperage at the startup surge than the 250.

Depending on the bulb manufacture, the 250 will either cook as soon as you fire it, or cook within the first week.

Also, transformer will not match load, which will cook it down mighty quick.

Bulb MUST match ballast.

no, you should only use a bulb matched to the wattage of the ballast.