New Co2 Gro - DIY Co2 - now in stock!

The new Co2 Gro, DIY Co2 generation system brings regulated Co2 application to the smaller grower. Grow with bottled Co2 without having to carry about large heavy bottles of Co2 by refilling and recharging your own bottle at home.

Check out Co2 GRO here

GorillaBox Tents Available Now!

GorillaBox Tents are available in a range of sizes to suit your individual growing situation. They Have a good build quality without being as expensive as other top brand tents on the market. They really are a good all round choice for many growers.

The tents are made from high quality, heavy-duty 210D and 600D Mylar fabric with high quality, heavy-duty zips.

Gorilla Box Tents - click here

Shogun Nutrients available now at Critical Mass!

Shogun Nutrients are available now instore and online! These legendary nutrients are great for both new and seasoned growers alike and deliver some impressive results.

Check out Shogun Nutrients now!

The Best LED Lighting Available - Huge Stocks

View all LED Grow Lights
Maxibright Daylight 660w pro LEDMaxibright Daylight 660w pro LED
Maxibright Maxibright Daylight 660w pro LED
Sale price£779.95
In stock
Lumii Black 720w/960w LEDLumii Black 720w/960w LED
LUMII Lumii Black 720w/960w LED
Sale priceFrom £264.95
Sold out
Adjustawatt 720w led - no ballastAdjustawatt 720w led - no ballast
Adjustawatt Adjustawatt 720w led - no ballast
Sale price£244.95
In stock, 12 units
Control LED Controller
ControLED Control LED Controller
Sale price£339.95
Sold out
Solar-tech 720w LEDSolar-tech 720w LED
Solar-tech Solar-tech 720w LED
Sale priceFrom £289.95
In stock, 11 units
Pulsar 720w LED - NO BALLAST
pulsar Pulsar 720w LED - NO BALLAST
Sale price£329.95
In stock
Pulsar MAX 720W LED Including Ballast
pulsar Pulsar MAX 720W LED Including Ballast
Sale price£344.95
In stock
Spectro Tech 300w LEDSpectro Tech 300w LED
ControLED Spectro Tech 300w LED
Sale price£374.95
In stock
Spectro-Tech 480w LEDSpectro-Tech 480w LED
ControLED Spectro-Tech 480w LED
Sale price£599.95
In stock
Spectro-Tech 660w LEDSpectro-Tech 660w LED
ControLED Spectro-Tech 660w LED
Sale price£699.95
In stock
Lumatek Zeus 600w 2.9 u/mol LED
Lumatek Lumatek Zeus 600w 2.9 u/mol LED
Sale price£899.95
Sold out

Love hand watering? - Check out our hand water and hand water pro kits

Hand watering is the most common method used to irrigate pots of soil and coco, it's a great method but creates a couple of issues that growers need to overcome. Firstly run off is created by hand watering pots to the recommended 20-30% run off, leaving pots sat in this run off is bad news for your roots and can cause slow growth, both our hand water kits utilise baseline trays to allow run-off to collect in the baseline brain provided which pumps it to a separate waste tank or drain.

Secondly hand watering multiple pots is a pain, our hand water pro kits contain a pump, pipework and telescopic watering lance to make hand watering many pots a breeze! Not only is this a quick and easy method to water many pots it's also much better at hydrating all the coco/soil in a pot as the watering lance sprays out like a shower head - no dry spots in your coco!

Introductory offer! 20% off all soil or coco when you buy any hand water kit instore!!!!

Hand water kits here!

Find us....

Critical Mass Systems Sheffield

Unit 4, Holbrook Enterprise Park,


S20 3GL

Monday, Tuesday, Wednesday & Friday: 9.30AM - 6PM

Thursday 9.30AM - 7PM (Late Night)
Saturday: 10AM - 5PM
Sunday: 11AM - 4PM

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