315W LEC/CMH Cannabis Grow Setup & Tutorial

by Nebula Haze

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315W LEC Grow Setup (For Hobbyist Growers)

• Average Yields: 5-10 ounces (we’ve harvested as much as 17 ounces, learn how)
• Recommended 2-8 plants
• Grow space: at least 2×4’ or 3’x3′ with a height of 5′ or more

About This Setup

The 315W LEC grow light (a brand name version of the “Ceramic Metal Halide”) is relatively new to the growing scene and is a popular alternative to HID lighting. It excels in the vegetative stage where it produces fast growth, though it also does a great job in flowering by producing strong, sparkly bud. LECs provide a significant amount of UV-A which may explain why the buds tend to look so glittery.

Pros: One bulb for the entire grow, great results, non-suspicious colored lighting, great for SOG

Cons: Needs significant height above plants, the LEC itself is pricey by comparison to HIDs

Learn more about growing cannabis with LECs

Cost Estimates

• Total Setup Cost: $940 + Cost of Seeds
• Estimated Electricity Cost: $29-58/month (based on $0.12/kWH to $0.25/kWh – see breakdown)
• Total Cost for Entire First 4-Month Grow (Setup + Electricity): $1056-$1172 ($106-235/ounce based on average yield of 5-10 ounces)
• Total Cost for Second Grow (Nutrients + Electricity): Up to $332 ($33-67/ounce based on average yields)
• If you follow these 8 simple steps you can harvest a pound (16 oz) or more with this system, bringing the per-ounce cost as low as $20/ounce after the first grow.

View a full growing tutorial using LEC grow lights

Complete Grow Supply List

This cannabis grow room setup list includes all the supplies you need to get to harvest.

Grow Light

• 315 LEC Grow Light
  • The model I use and recommend is the 315 LEC Grow Light from Sun System with a “Vertical Bulb” orientation. I use a brand name Philips 4100K colored bulb from seed to harvest (included).
  • (optional) There is a 3100K color bulb available for the flowering stage which may help increase bud fattening. Get the brand name Philips bulb or a generic version.
  • Cost: ~$400

Sun System 315W LEC Grow Light

Grow Space

• Grow Tent Recommended Sizes
  • 2’x4’x5′ (smallest size – be careful of plant height) – an example is Apollo Horticulture 48”x24”x60”
  • 2’x4’x6′ (recommended size) or 3’x3’x6′ – I use the TopoLite 48″x24″x72″ Grow Tent
  • 4’x4’x7′ (jumbo size – never worry about space, can be upgraded to a bigger light later) – an example is Apollo Horticulture 48”x48”x80”
  • Learn more about grow tents
  • Cost: ~$60-100
• Exhaust Fan
  • A quality 6″ inline exhaust fan works best. Avoid small cheap “booster” fans as they usually don’t have enough power to exhaust all the hot air effectively. Hang from inside tent to help keep quiet.
  • Learn more about choosing and setting up an exhaust fan.
  • Recommended: Can Max 6″ Fan – 334 CFM
  • Cost: ~$130
• Carbon Scrubber
  • Must be used with an exhaust fan to effectively remove smells! Learn more about controlling odors.
  • Recommended: 6-inch Carbon Filter, 6″ x 16″ version
  • Cost: ~$65

Plant Pots

• Growing medium: Coco coir or soil (hydroponics for more advanced growers)
• Containers: Smart pots or Air Pots between 2 and 7 gallons
• Recommended: One bag of this coco potting mix which is enough to fill 5 x 3-gallon smart pots
• Cost: ~$70

Nutrients

• You need a “vegetative” or all-purpose plant nutrient for the first part of your plant’s life
• You need a “bloom” or low-nitrogen nutrient for the budding phase
• Many nutrient systems have a nutrient schedule so you give your plants the right ratios for each stage of life
• Always start at half strength with a new base nutrient system because the recommended strength is typically too high for cannabis
• Get examples of great cannabis nutrients
• Recommended Base Nutrients: General Hydroponics Flora trio (use at half strength) + CaliMagic (use at full strength)
• (Optional) Bloom Supplement: General Hydroponics Floralicious Bloom
• (Optional) Root Supplement: Botanicare Hydroguard
• Cost: $50-100

 
General Hydroponics Flora Trio and CaliMagic

Other Supplementary Items

• Get your seeds – $5-12/seed (on average, can be more or less depending on the breeder)
• 24-Hour Timer (to put your grow lights on a timer so the plants get a day and night period on a schedule). Why do cannabis plants need to be on a day/night schedule? What about autoflowering light schedules? – $10
• Water containers (I personally use a 3-gallon or 5-gallon water jug to mix up nutrients, but anything can work) – Much cheaper at Wal-Mart ($5-15) than online!
• 6″ Ducting and Ducting Clamps – to connect your fan and carbon filter together – $15
• Extra pair of 1/8″ Rope Ratchets (sooooo handy) – These can be used to hang your grow light or carbon filter from inside the tent, and still be able to easily move it up and down without needing any strength. Your grow light usually comes with a set of rope ratchets, but it’s a great idea to get an extra set to hang the carbon filter – $10
• Thermometer/Humidity Monitor with a probe so you can keep track of the temperature inside the tent – $15
• PH Test Kit – Prevent potential nutrient deficiencies by testing the water pH: https://www.growweedeasy.com/ph – $15
• Measuring spoons for measuring out your nutrients (many people already have these) – $10
• Learn about other cool growing tools

Estimated Cost: $940 plus the cost of seeds

See Additional Grow Setups

Cannabis plants growing under a 315 LEC Grow Light

CMH grow lights produce extremely fast and healthy vegetative growth. These plants are only 29 days old.

Cannabis plants flowering under a 315 LEC Grow Light

A 315 LEC (CMH) Grow Light Fixture by Sun System

Example of buds grown under a 315 LEC grow light from seed to harvest in this setup (pictured above and below)