Everything you should know about black weed

All cannabis lovers adore well cured, sticky, pungent and potent cannabis. Normally your buds are a shade of green, often with a pleasingly sticky white resin coating. But some dark-coloured weed strains can produce deep-purple hues that can look almost black in appearance. Such exotic colourations are relatively rare but highly sought after.

Main factors inducing dark colours in weed plants

If you want to grow black weed, you need to be highly selective in your choice of cannabis seeds. Select strains known for producing dark coloured buds. These can be either feminised cannabis seeds or autoflower seeds. But other factors can help the grower keen to grow dark coloured buds. The key to growing black weed is to grow cannabis strains with the highest pigmentation levels and to steer the grow conditions to amplify the effects. Then keep your fingers crossed for the right phenotypes to turn up!

•    Bloom conditions. Cooler temperatures in bloom, especially during the ‘dark’ lights-out period are known to promote the production of cannabis pigments which darken the foliage. Indoor growers can try allowing ‘lights-out’ temperatures to drop temperatures down to around 17-18º (~63F)

•    Ice. Some growers occasionally pile ice around the base of the main stem during bloom to assist the effects of cool conditions and colour change.

•    Indica/sativa cannabis seeds. Many of the strains which exhibit the darker colours are indica strains, though some sativa strains can also show dark colours.

•    pH is thought to influence dark pigmentation within the cannabis plant. Often the pH in soil-grown cannabis is kept in the range pH 6-7. Allowing pH to drift nearer to pH 7 (i.e. less acidic) is thought to help promote darker coloured weed.

How to distinguish natural dark colours from sooty mould?

Nothing impresses a cannabis connoisseur as much as some banging buds with an out-of-this-world appearance. Black weed is one of those cannabis curiosities that never loses its appeal. In reality, you will need the right cannabis seeds, good environmental control and a little bit of good fortune to find the right phenotypes.

But black sooty mould can also give your plants a dark appearance. The experienced grower will work hard to avoid the conditions that can promote cannabis mould and can easily spot the difference between mould and plant pigmentation. If it does appear you will notice the mould can be scraped off the leaves and is not part of the plant’s natural pigmentation.

Cannabis mould can rear its ugly head in humid conditions, especially in grow room cluttered with waste foliage/leaves. If you are unfortunate enough to suffer from mould, the following specialist advice may be useful.

Best cannabis seeds to grow dark plants

You will rarely feel such a sense of satisfaction and pride in your harvest as you will with a well-stacked grow room full of buds in uniquely dark/black colours. But you will need to start with the right cannabis seeds. Here are Dutch Passion’s top-two recommendations for anyone hoping to pull off a harvest of black weed. Note that not all the plants will produce the dark/black colours but some phenotypes will.

Auto Blackberry Kush: XL yielding indica autoflower strain with fast 10-week grow cycle

Auto Blackberry Kush (Blueberry x Genebank dark hash plant) is an autoflower seed variety that produces phenotypes which include very dark purple colourations. Grow these well and they yield XL quantities of crazy-dark coloured buds that can cure to an almost-black appearance.

Auto Blackberry Kush grows from autoflower seed to harvest in around 10 weeks, though some phenotypes can be ready in as little as 9 weeks making this one of the fastest autos in the Dutch Passion collection (only Auto Blueberry can match the growth vigour/speed).

Black Lebanon: the legendary sticky hash plant from the Super Sativa Seed Club

Black Lebanon is an indica photoperiod feminised seed variety using the original Black Lebanon Hash Plant 1980’s genetics. The Super Sativa Seed Club are a sister-company to Dutch Passion, established in the 1980’s with a unique gene bank of original 1980’s (and pre-1980’s) cannabis genetics. Black Lebanon is a fully proven classic.

Her name comes from the ability to produce dark, occasionally almost black buds/foliage on some phenotypes. The spectacular bud appearance is heightened by the thick resin layer. Hash or cannabis concentrate fans will enjoy generous quantities of extracts and the THC levels (around/just above 20%) ensure a long lasting, satisfying effect.

How to grow dark cannabis plants

Be patient and focus only on stable, proven dark coloured cannabis strains. Not all the phenotypes will be dark. But some may, and one or two may exhibit particularly dark buds which may cure into a very dark, almost black colour.

If growing photoperiod feminised cannabis seeds you can take cuttings of any outstanding specimens to preserve as mother plants. Or you can try re-vegging the plants that showed the best combo of colour, potency and taste after harvest.

The ‘black’ colour is technically a very dark purple caused by intense production of Anthocyanin plant pigments. In lesser quantities these Anthocyanins can produce delicate pink or purple/blue hues. In higher concentrations these plant pigments, also known technically as flavonoids, produce the dark purple or almost-black weed.

‘Normal’ green weed contains chlorophyll (as does black weed), but unlike black weed it doesn’t have sufficient anthocyanins to mask the green colour and produce the trademark black buds.

Is black weed more potent?

Not necessarily, but it does capture everyone’s attention thanks to the rare, striking appearance. Plant pigmentation levels are not directly related to total cannabinoid content. Much depends on the grow environment. Grow a dark-weed strain badly and you will find a poor terpene profile and sub-optimised cannabinoid levels. But grow a dark weed strain well and you can expect 20%+ THC levels and a rich pungent aroma. Combine these qualities with rare black colours and your friends will empty the jars faster than you can fill them!