MH or HPS for stretch

[miser66]

Recently I got a new HPS that doesn't have as much blue spectrum as my other. One of my plants at 18days into 12/12 has 1 of its tops reaching under the bluer light and that top is clearly more vigorous, stockier with tighter internodes then the tops under the orange light that are stretchier and not as lush green. So its making me wonder if anyone uses MH for the first few weeks of flowering before switching to HPS. Any opinions.

 

[rennie37]

mh for veg (blueish light)
hps for flowering (redish light)

 

[sound1744]

yea man their more likely too stretch under a HPS than a MH.

 

[sedate]

So its making me wonder if anyone uses MH for the first few weeks of flowering before switching to HPS. Any opinions.

The difference between a plant vegged under an HPS and one vegged under an MH is night and day.

HPS absolutely produces more stretching.

Many growers will use a 2:1 ration of MH to HPS bulbs for this exact reason - I'm actually planning an upgrade in that very direction myself.

IMO, taking it all the way through flowering like this produces really tight, tight colas.

When one examines the spectrum curves on higher temp HPS bulbs - like, say EYE's Hortilux - you don't get nearly the added blue spectrum you'd get with an MH in the HID mix.

 

[sedate]

2:1 ration of MH to HPS bulbs

Ack.

That should read "2:1 ratio of HPS to MH bulbs" - two HPS's for one MH.