Pruning Indoor Plants for Grow Lights

Pruning and training plants for cultivation under indoor grow lights is such an important technique to increase productivity—it really isn't just "another tool in the toolkit" for the indoor gardener as far as I'm concerned, it's mandatory—especially if you are cultivating fast-growing, heavy fruiting annuals.

Well here she is—my indoor garden in early December 2014. All the plants you can see were started from seeds in late August / early September. I have two 600W HID grow lights (a metal halide over the tomato on the left and an HPS over the chile peppers on the right) - in the far corner I have a 1000W HPS over my cucumbers and some other pepper varieties. You will note that I haven't got around to air cooling the 600W HPS on the right. I just haven't had the time to change my ducting arrangements. In fact, I think I'm going to make life easy for myself and swap this out for an Adjust-a-Wing reflector instead, just for a little variety. The air-cooled reflectors are a Sun Star 6" and a Magnum XXL - both by Sun Systems / Sunlight Supply.

Clean, thriving grow room—I love my indoor garden!

The tomato in the foreground is a variety called "Sub Arctic Plenty" - it's a determinate variety that produces fruit very early. That said, mine is still very much in vegetative mode in this photo! It is growing in a deep water culture system by Current Culture—a fantastic company that creates awesome DWC systems (both single and modular) on epic scales! Because reservoir temperatures are so important, I've hooked it up to an aquarium chiller (you can see the two black hoses in the bottom-left corner of the photo) to make sure that nutrients remain cool. This is so important for DWC and other "media-less" hydroponic growing systems (e.g. NFT, Aeroponics)

Sub Arctic Plenty Determinate Tomato thriving in a deep water culture system by Current Culture, California.

As you can see I've used a mixture of framework (bought from my local garden centre) bamboo poles and wire to both support this tomato plant and to encourage it into a low, wide form. I want a really wide canopy to fully exploit all that light coming from the 600 watts above. It was necessary to thin the plant out in the middle so that it didn't get too dense as that might be an invitation to powdery mildew. All looks good so far, apart from the fact that I over-fed the plant slightly, not taking into account that DWC requires far lower nutrient concentrations. After speaking with some grower buddies we settled on an EC of 1.0 mS (rather than the 2.0 mS I was feeding it previously!)

Sub Arctic Plenty tomato spread out low and wide to bask under this 600 watt metal halide grow lamp

Here she is looking green and lush underneath the 600 watt metal halide. I'd like to start seeing some fruit soon but, for now, this 'daylight' spectrum, rich in blues, seems to be what this tomato needs.

A screen of green (scrog) style chile pepper canope

Moving on ... here's a little arrangement I'm really proud of. You're looking at four Tokyo Hot chile pepper plants. Three are in five-gallon Smart Pots (an awesome, breathable fabric container that turbocharges your plants!) and one is in a Uni-Slab rockwool slab by Grodan—a miniature slab designed for just one plant. All plants are doing great, especially since I trained them to spread out over this soft-mesh netting and removed the lower foliage that wasn't receiving much light.

Using netting to create an level canopy of fruiting sites

When a branch / growing tip pops up, I simply tuck it back underneath again. Tokyo Hot lends itself well to this technique of lateral training because the branches are fairly flexible (unlike Yolo Wonder which snaps if I even look at it the wrong way!) - Also Tokyo Hot's leaves are relatively small so, despite there being four large plants under this netting, it doesn't seem to get too dense and all plants get a fair shot!

Lower parts of my chile plants were stripped of their branches to allow the plants to focus on the canopy

She looks so bare underneath! But this allows the plant to focus all her attention on the canopy, where all the action and fruit sites are. Being the "boss" over your plants like this and shaping them to exploit the potential (and limitations!) of your grow lights is a crucial technique for all indoor growers to master, unless you're growing flat leafy crops that don't grow more than an inch or two high!

My first green Tokyo Hot chile peppers!

I haven't tasted these yet, but I imagine them to be fairly pokey! I'll wait until they turn red and give you a report!

Sub arctic plenty determinate tomato plant under a 600W metal halide HID grow light

Finally, here's my Sub Arctic Plenty tomato again, now under a HPS (high pressure sodium) 600W to encourage some fruit development.

If you want to see the JUNGLE that my grow room was before I got it into order, make sure you check out this video I made—it should give you a laugh at the very least! :)

Pruning and Training Indoor Plants for Grow Lights

Pruning and Training my indoor plants and regaining some control over my garden!

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