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More people than ever are growing CBD-rich cannabis seeds, and not just medical growers. Many recreational growers also find that they enjoy the smooth, chilled effects of CBD weed from time to time. The optimum harvest time will vary from one CBD-rich variety to the next, so accurate strain descriptions from your cannabis seed supplier are critical. But there are some important additional aspects to consider when deciding on the best time to harvest your CBD crop.
CBD rich cannabis strains come in a variety of types. Some are high-CBD, low-THC strains which have so little THC that there is no psychoactive ‘high’. Others have a 1:1 CBD:THC ratio, often with a moderate high. You can grow CBD-rich feminised seeds or autoflower seeds, indica seeds or sativa seeds, all with their own cannabis seed-to-harvest times.
The following summary tables show you precisely what to expect. Growth cycles are very much in line with those you have come to expect from traditional THC rich cannabis seeds.
CBD-rich feminised cannabis seeds require a period of veg growth with 18+ hours of daily light. This is typically 4-6 weeks, depending on the grower. Bloom only begins once the plants start their 12/12 indoor cannabis light cycle (i.e. 12 hours of daily light followed by 12 hours of darkness).
| Variety |  |
 |
 |
| CBD Charlotte’s Angel | 11 weeks | 15% | <1% |
| CBD Compassion | 8 weeks | 8% | <1% |
| CBD Kush | 9 weeks | 7.5% | 5-10% |
CBD-rich autoflower seeds are harvested around 9-13 weeks after germination, depending on strain and phenotype. Indoor growers find a cannabis light cycle with 20 hours of daily light produces great results. CBD autoflower seeds are often viewed as the fastest and easiest way to grow CBD weed. It’s worth mentioning that increasing numbers of Dutch Passion recreational growers give great feedback on the soothing, manageable and supremely enjoyable effects of the 1:1 THC:CBD strains.
| Variety |  |
|
|
| CBD Auto Blackberry Kush | 13 weeks | 15% | <1% |
| CBD Auto Charlotte’s Angel | 13 weeks | 15% | <1% |
| CBD Auto Compassion Lime | 10-11 weeks | 13.5% | 5-10% |
| CBD Auto White Widow | 9-10 weeks | 7.5% | 5-10% |
CBDV (Cannabidivarin) is a relatively new cannabinoid to the medical cannabis scene. With no psychoactive high, it is of interest to many medical growers. Auto CBD-Victory produces buds with around 4-6%CBDV and a similar amount of CBD. Users report soothing, relaxing and calming effects.
| Variety | |
 |
|
| Auto CBD-Victory | 9 weeks | 4-6% | <1% |
Related:
CBDV, what does this non-psychoactive cannabinoid offer?
Those growing CBD rich cannabis strains generally want to hit the highest total cannabinoid content possible. The most experienced growers can keep their plants in the nutrient and optical sweet spots at each stage of growth. In general, those aiming for the highest CBD levels often tend to avoid harvesting their buds too early, instead they will wait patiently for their buds to fully ripen and finish swelling.
Many CBD-weed growers use a small loupe (magnifying glass) to look at trichome appearance. Generally, most wait until the point where most of the trichomes have turned from clear to cloudy and use that as their harvest point. Many of the new hairs (pistils) may be orange at this time and the buds, to the experienced eye, will look ripe. Indoor growers tend to consider trichome appearance, pistil colour and general bud appearance when judging ripeness.
Outdoor CBD weed growers should use much the same approach as indoor growers and consider general bud/trichome appearance. However, prevailing outdoor weather conditions can sometimes necessitate an early harvest. In these cases, CBD levels may not have quite peaked, but sometimes outdoor growers have to consider compromising between their preferred harvest date and a realistic one.
The illustrations show that harvest-ready CBD cannabis plants look just the same as traditional THC-rich weed. Visually there is nothing that identifies a plant as being CBD-rich or THC-rich. The differences are on a molecular level, affecting the cannabinoids produced by the trichome resin glands. The chemical composition of this cannabinoid profile is determined by the genetics in your original cannabis seeds.
Note that it’s not just a choice between THC and CBD. The Dutch Passion Special Cannabinoid cannabis seed collection is the best place to go if you’re interested in other new cannabinoids such as CBG, THCV, CBDV etc. Again, use the usual techniques of assessing trichome, pistil and general bud appearance to judge when your plant has ripened and is ready to harvest.
Not all CBD-rich cannabis seeds are fully stabilised leading to phenotype variations with differing CBD levels. These are often called ‘chemotype’ variations. Choose a reliable cannabis seed supplier, noting that a few cannabis cup wins are a sure sign that your seed bank takes their craft seriously.
The main grow related tips are to keep your plants in the nutrient and optical sweet spot from cannabis seed to harvest. That may seem easier said than done, but most growers gain experience in this regard with each harvest. One particularly useful tip for those that see-saw from over-feeding to under-feeding when using bottled mineral nutrients is to consider slow-release organic nutrients such as those from BioTabs.
These slowly dissolve, making the entire grow process easier with a greater working latitude for less experienced growers and are very highly recommended. Using slow-release organics may mean your only nutrient demands may be for a general-purpose bloom nutrient (and maybe a PK boost) in mid/late bloom. Many pro-growers also use slow-release organics, finding it eliminates the complexity of nutrient (mis) management increasing the chances of optimised quality/quantity at harvest.
In terms of lighting, most serious self-sufficient hobby growers and many licensed professional producers now firmly insist on quality LED lighting. With the optimised spectrum and inherently lower levels of heat stress compared to HPS, LED produces a higher total cannabinoid content than ageing HPS tech. With no replacement bulbs and lower running costs, LED is an expensive but undeniably essential grow room upgrade for the quality conscious grower.
One final recommendation is to use supplemental UVA/UVB lighting. This is often applied for 2-3 hours per day for the last 2-3 weeks of bloom and adds important Ultraviolet light wavelengths that LED can’t currently deliver. UV LED chips are still not as cost-effective as fluorescent tubes at delivering UVA/UVB, but that may change in coming years. UVA & UVB have been demonstrated to add boost total cannabinoid content by modest, but significant, levels.
Growing CBD rich cannabis isn’t any more demanding or complicated than growing THC rich cannabis seeds. Start with the best CBD seeds you can buy and aim to grow them in an optimised, stress-free grow environment and you can expect connoisseur quality results!
