When should plants be switched from propagation to MH lights? & other noob questions.

Hello everyone!!
This is my first post after i realised lurking these forums for so long warranting coming and getting involved
I tried the search bar but nothing came back.. sorry in advance if its been answered a bajillion times.

Im currently growing 5 of my seedlings in small rockwool plugs under three 20w CFLs; just the regular CFLs you get in the shops and i was wondering at what height they should be before i should switch to my MH light? Its a 400w thing so i dont want to be switching it on when my CFLs can do the job adequately, so as to save electricity costs etc, and also because my tiny propagation cupboard doesnt have sufficient ventilation to do anything but burn the little things with such a hot lamp in it.


Also sneaky second question - can i use rockwool cubes in an NFT set up? a website said rockwool isn't a suitable a medium for NFT.

Cheers!!

I personally wouldn't use anything less than 100w of actual CFL's (not the equivalent)
Once your plants get a good Set of fan leafs place the MH in there about a 12in to 18in over ur plants.
Have fun buddy and happy growing

You can put the straight under the mh, I did I have 400Watt mh I put mine under it as soon as they popped. They start growing much faster and better as soon as you change from cfl's to mh. I grew mine for two or three weeks under mh then switched to hps being you get a bigger yield but takes longer I have mh/hps switchable ballast. Hope this was helpful Happy growing

I'm a bit confused. To answer your 1st question you can use your MH at any time since a lot of people use it for veg.....10" -12" is fine....but if you do not have proper ventilation how were you going to use your MH?

Also, like the previous poster mentioned, if you have an electronic ballast that will handle MH and HPS, then that is not a bad investment for the future...if you are going to invest in that style of ballast and another 400W HPS bulb....
Have fun and good growing!

Height is totally depending on what you want from your grow. I'm gonna work on the assumption that you have a veg cupboard, which you plan to use purely for early veg, and then the MH will be in a seperate tent/cupboard??

Do you plan to switch to 12/12 when introducing the bigger light? If so then 12-18" is a good rule of thumb, but this depends on the strain, your useable grow height? Also If you do in fact have a seperate flower room it may be worth having a more regular harvest of smaller plants. There are so many variables lol.

I hope this has helped a bit, but in general, a bit more info helps us help you

One thing I will say, most shop bought CFL's are 2700k light spectrum (orange/yellow) it's worth spending time online to get blue bulbs 6500k for vegging, and with the smaller CFL's in particular, try and keep the distant from light about 2" to avoid stretch.

If you need any more help, please ask, and if you are a UK grower I can point you in the direction of good CFL's, it can be worth paying the little extra for better bulbs

Prompt helpful replies - you guys are the best!
Ill go get a 48w two strip T5 light tomorrow with 6500k tubes- will be an adequate light set for a 5 or so plant nursery or would a 96w four strip one be better?

I didnt want to use the MH from the start because it's 400w and i guessed might be overkill for such tiny plants.

Hetty - thats exactly the plan, i have a small cupboard (50cm x90cm x70cm) for early veg and a bigger closet (120cm x 120 x 470cm) for the MH/HPS set up.
My plan is to veg as much as possible with these CFLs then put them in the other room with the bigger light still on 18/6 until theyre about 12" tall then 12/12.

Suppose i really meant to say how will i know at what point should i bring them out from this CFL set up to the HID - so when they have a decent set of fan leaves then?
Yeah im a UK grower - you'd have thought maplin of all places would have 6500k lights, but alas they dont.. pffft! any direction giving would be grand

Thanks for your help guys

http://stores.ebay.co.uk/greenlampltd if you don't use ebay or paypal, their is a phone number somewhere, you can call direct. The bulbs are some of the cheapest out there, but really good quality, and they ship quick too. Oh I use some of the 30w 6500k bulbs, they are spiral shape, and while very bright, are pretty squat, and difficult to get a good spread (the 30w CFL's in 2700k are a much better spiral shape....go figure) i'll be trying the 45w when i renew mine. If you ever decide to go for one bigger CFL, Plug n Grow are brighter per what, have better light span, and better built.

http://charlieshydro.co.uk/ - these guys are the best mail order company i've ever dealt with, full stop, and pretty competetiive with price

Also maplin sell these small rotary fans for about £7-8 quid, that look like big PC fans, but plug you can whack a plug straight on them as they are 230/240v. Because they are small and light, they are really handy for grows. I use one in my veg cupboard to circulate, and one under my HOS bulb to keep it and the top of the plants cool.

please excuse the sorry looking plants in my flower room. Cal/mag deficiencies and spider mites have cuased havock, but hopefulyy they are learning curve that you can side step

rexthered said:

Prompt helpful replies - you guys are the best!

Hetty - thats exactly the plan, i have a small cupboard (50cm x90cm x70cm) for early veg and a bigger closet (120cm x 120 x 470cm) for the MH/HPS set up.
My plan is to veg as much as possible with these CFLs then put them in the other room with the bigger light still on 18/6 until theyre about 12" tall then 12/12.

Suppose i really meant to say how will i know at what point should i bring them out from this CFL set up to the HID - so when they have a decent set of fan leaves then?
Yeah im a UK grower - you'd have thought maplin of all places would have 6500k lights, but alas they dont.. pffft! any direction giving would be grand

Thanks for your help guys

Click to expand...

I've never used a T5, but heard nothing but good things from dozens of respected growers, so make of that what you will, and I would have thought the 2 strip would be fine, and maybe keep a couple of the 20w cfl's to give a better light spectrum, and a little extra light. Both Veg and Flower need blue and yellow light, but veg needs more blue, and flower more yellow. I'm trying to keep it basic and not overwhelm, but you'll read loads more about light spectrums and lumens as you go.

Oh yeah and surpised maplins didn't have blue bulbs... I tried about DIY stores and 3 local specialist Light shops, and 2 hydro stores, and only managed to find a couple of 125w plus bulbs at the hydro's....people needs to be keeping up!!

Ive used both (4 75w CFL'S and 1000w MH) at different times and sold my MH light and just use my CFL'S for veg still got 1000w HPS for flowering but ive had better results with CFL during veg mostly because I had problems controlling the heat from MH and had to keep it so far away. But with CFL you can keep it 2-4 inches away and have no problems at all. Personally I recommend CFL through all your veg and HPS for flowering.