Need Tighter, Thicker Mother Plant Growth (T5 vs MH vs CMH?)

To get tighter internodal growth and thicker, less spindly growth, which light would be my best bet? I'm currently using CMH and MH, but had better (albeit way too slow) growth with T12's (I would never fill a space with T12...just sayin')!

My canopy space is 4 x 10 with 2, 315-watt CMH lights and 1, 1000-watt MH light (currently dialed down to 600 watts). I'd like to do maximum volume (300 clones/month would be nice, I've hit that mark a few times) and right now I've got 8 mother plants (four in 7-gallon containers, four in 3-gallon) and 6 smaller mothers in training (1-3 gallon). At these sizes, I should be able to fit 10-12 plants.

I keep the lights as close to the plants as I can, but some strains (Biscotti, Papaya Cake, Lava Cake, Oreoz) are just getting super lanky on me and I end up pruning off a lot thin, spindly waste. The other plants that are growing good, grow too fast and I'm taking cuts every 2 weeks, but they're still getting too tall too quickly.

I add Silica, use a bloom based nutrient mix (occasionally add in veg for some nitrogen when low), and add a bit more calmag and the light schedule is currently 18 hrs. I've tried lowering nutes, but then deficiencies start showing up.

Would T5's or LED be better to achieve what I'm looking for or is there something else I'm missing?


Thanks!

A 1000w MH bulb running at 600w is probably running at super low efficiency. Probably only getting like 300w of actual light. Turn the light up to 1000w. And use quality bulbs. Philips. Ushio. Gavita. What is the spectrum of your bulbs? 3100k? 4200k? Maybe switching the MH to a 7000k would help. Turning the MH up to 1000w will get you 40w/sq ft which should be enough to grow healthy plants. Are you growing in a tent or an open area? If its an open area im betting you are missing out on a lot of reflected light which i feel helps the plants really bulk up and grow tight nodes. You shouldnt have to keep your lights "as close to your plants as possible" if your running enough power.



Tight as a nun on sunday


This is my 5x5. They spent the second half of veg in there under a 4000k MH bulb...

Tightest internodes I ever grew were under a 6400k t5 HO, 4 bulb light. I kept it about 4 or 5cm from the tops of the plants.
I don't know how modern LEDs will do yet, my new light is on it's way. Guess I'll know in a few weeks.

JoeBlow5823 said:

A 1000w MH bulb running at 600w is probably running at super low efficiency. Probably only getting like 300w of actual light. Turn the light up to 1000w. And use quality bulbs. Philips. Ushio. Gavita. What is the spectrum of your bulbs? 3100k? 4200k? Maybe switching the MH to a 7000k would help. Turning the MH up to 1000w will get you 40w/sq ft which should be enough to grow healthy plants. Are you growing in a tent or an open area? If its an open area im betting you are missing out on a lot of reflected light which i feel helps the plants really bulk up and grow tight nodes. You shouldnt have to keep your lights "as close to your plants as possible" if your running enough power.

Click to expand...

Thanks Joe, I guess I always thought that since the 1,000 watt normal veg space is something like 5x5 and I was using a smaller area with smaller plants I could get away with lower power (and save a bit of $) but what you say makes sense. I'll crank it up a bit and see how things go.

For bulbs, the MH is a 6500k, but it's the cheapo "Grow Bright" brand. The CMH are the Philips bulbs mentioned. I looked all over for the 4200, but all I could find were the 3100K.

I'm in a tent. The total size is 10x10 with all the plants on one wall taking up the 4x10 space mentioned. For space requirements, I actually have my 4x4 flower tent inside of this tent and the rest of the space has a 4x2 table with a t5 and my bonsai mother plants.

Thanks for the advice. I'll crank the light up and look into sourcing better bulbs.

Jimbo the Gael said:

Tightest internodes I ever grew were under a 6400k t5 HO, 4 bulb light. I kept it about 4 or 5cm from the tops of the plants.
I don't know how modern LEDs will do yet, my new light is on it's way. Guess I'll know in a few weeks.

Click to expand...

Nice. Which LED did you go with?

Titikshu said:

Thanks Joe, I guess I always thought that since the 1,000 watt normal veg space is something like 5x5 and I was using a smaller area with smaller plants I could get away with lower power (and save a bit of $) but what you say makes sense. I'll crank it up a bit and see how things go.

For bulbs, the MH is a 6500k, but it's the cheapo "Grow Bright" brand. The CMH are the Philips bulbs mentioned. I looked all over for the 4200, but all I could find were the 3100K.

I'm in a tent. The total size is 10x10 with all the plants on one wall taking up the 4x10 space mentioned. For space requirements, I actually have my 4x4 flower tent inside of this tent and the rest of the space has a 4x2 table with a t5 and my bonsai mother plants.

Thanks for the advice. I'll crank the light up and look into sourcing better bulbs.

Click to expand...

The philips 3100 should be ok too. You just need to get the watts up. I would definitely look into getting the Ushio 1000w MH bulb.

Titikshu said:

Nice. Which LED did you go with?

Click to expand...

sf1000 from Spider farmer. I'm just setting up a very small space for one plant. I'm an outdoor grower now, and need something to keep me busy in the off season, especially as the entire province entered lockdown on Boxing day. I used to grow indoors, so I'm looking forward to seeing what I can do with a qb style light.