I’ve been reading a lot of conflicting information about this. Some people are saying HPS causes more stretch with quicker growth and others are saying MH causes more stretch with quicker growth. Who is right? Does anyone have experience vegging with both? I’m currently in early veg and have both HPS and MH bulbs and I’m wondering which one I should use. I’m trying to get as much stretch as possible in early veg before I flower under a fluence spyder-x LED. Thanks!
Does HPS cause more stretch than a MH?
- Thread starter Kushizle
- Start date
SPLFreak808
Well-Known Member
Potential growth speed is regulated by overall (ppfd) par/wattage, in the same footprint, 400w of metal halide will outgrow a 250w hps and vice versa.
A heavy ratio of far red to red will encourage stretch (HPS), where a lack of far red will keep them tight (MH).
Fwiw, I've vegged/flowered with both plenty of times & while my HPS plants always had a bit more stretch, they also had the biggest fan leaves, every time.
A heavy ratio of far red to red will encourage stretch (HPS), where a lack of far red will keep them tight (MH).
Fwiw, I've vegged/flowered with both plenty of times & while my HPS plants always had a bit more stretch, they also had the biggest fan leaves, every time.
Sweet thanks for the reply. I’ll go with the HPS for now
Notthecops
Active Member
I see a big difference in using MH over HPS for veg. As mentioned above, less stretch with MH, but also thicker, stronger branches. Keep those nodes tight using MH in veg and it will pay off with nice colas when you flower with HPS.
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Less *stretch* with MH as opposed to HPS, not less "stress". I assume that was a typo, but I want to clarify for other readers just in case.
Notthecops
Active Member
Yes, thank you...I’ll edit it
Logan Burke
Well-Known Member
HPS, by nature, will stimulate more stem growth and less foliage growth. MH essentially has the opposite effect, causing less stem growth and more foliage growth. This is one reason why, when I'm concerned with vertical space during a grow, I will leave the MH bulb in until the stretch phase is over.