Marijuana harvesting cycle is like the last two minutes of a tied Super Bowl game. Everything that happened before could be perfect, but it’s the end of the game when the whole season is on the line.

The time when you cut, dry, cure and store your crops is the crucial end of the season for marijuana growers. And as in pro football, unforced errors can cost you the entire game. Most of us have made harvest mistakes and paid dearly for it. Let’s analyze marijuana harvesting mistakes so you avoid them and have a perfect finish to your marijuana growing game.

Harvest Timing Mistake #1: Relying On Bloom Phase Estimate

The majority of growers rely on the marijuana seed breeder’s bloom phase duration estimates as the major determinant in when they harvest their plants. If the breeder says bloom phase lasts “65 days,” the grower waits until 65 days have passed in bloom phase, and then harvests. This ignores the fact that marijuana plants aren’t machines whose flowering performance can be predicted with generic specificity. Indeed, many factors influence the length of long bloom phase and optimum harvest timing. These include:

  • Plant phenotypes, which can vary even among clones and high-quality seed-grown cannabis plants.
  • Grow op environment conditions.
  • Whether pests and diseases have attacked the plants and to what extent if any those attackers were defeated by the grower.
  • The quality and implementation of the feed program.
  • The quality, intensity, height, and placement of grow lights
  • The type of marijuana growing, e.g., deep water culture, soil, soilless mix, rockwool, coco coir, aeroponics, etc.
  • What cannabinoid and terpenoid mix and percentages the grower wants from his or her marijuana buds.
  • The grower’s desire for the heaviest harvest weight possible–versus harvesting at peak potency.

I’ve seen bloom phase durations that were as much as plus or minus 20 days from what the breeder recommended. For example, I use a product called Bud Ignitor that stimulates earlier floral development so my crops finish faster than the breeders predict. Use breeder bloom phase estimates only as a generic approximation, not as the final word on when to harvest.

Harvest Timing Mistake #2: Inadequate Monitoring of Resin Glands

Instead of relying solely on predictions about bloom phase duration, pay close attention to your resin glands. Marijuana resin glands are a plant’s version of a golf ball on top of a tee. The round glandular head (the golf ball) is where most of the cannabinoids, terpenoids and flavonoids are produced and stored, although some resins are in the gland stalk (the tee), and in bud leaf material. When resin glands are at their peak size and freshness, stalks are sturdy and vertical and glands are round, large and clear.

Depending on strain genetics and to varying degrees, resin glands go cloudy and/or amber as peak bloom phase advances. But as peak bloom expires and harvest time approaches, resin glands begin to fall off the stalks, and some stalks bend and topple.When more than 20% of the glands are cloudy or amber, the round glands have fallen off the stalks, or the stalks are bent or collapsed, peak resin potency has passed and buds should be harvested.

Starting in peak bloom, use a magnifying device to examine the resin glands that are several inches below the topmost canopy of your plants.

In almost all cases, resin gland condition is the single most important indicator of peak potency harvest timing, with the breeder’s bloom phase estimate a distant second.

Marijuana Harvest Timing Mistake #3: Harvesting Too Early

Some cannabis strains when fed and lit properly gain 30-45% of their bud weight during the last 2-3 weeks of bloom phase. For some late gainer strains when I’ve fed Overdrive in the final third of bloom phase, I’ve seen buds nearly double in size. If you harvest too early, you miss out on that weight gain, which means missing out on 30-45% of your profits.

Harvesting marijuana too early also means a significant percentage of cannabinoid, terpenoid and flavonoid production is lost. But it’s not just that resin gland heads have less time to swell up, it’s also that the compounds inside have less time to fully mature and ripen. For example, a strain harvested at optimum potency at 63 days in bloom phase may test out at 23.5% THC, but the same strain harvested at 55 days in bloom may test out at only 19% THC.

Harvesting too early creates a different psychoactive experience compared to harvesting later. And if you’re a trichome (resin gland) farmer growing primarily to make dry sift, bubble hash, kief, or processed cannabis concentrates, harvesting too early robs you of some of your resin gland harvest.

Marijuana Harvesting Mistake #4: Harvesting Too Late

If a grower isn’t paying attention to resin gland color and structural integrity, and/or is waiting for the breeder’s bloom phase duration date, the crop can become overripe. The resin glands degrade, so a percentage of resins are lost to decay and desiccation.

Also, the ratios and percentages of cannabinoids, terpenoids and flavonoids change as the crop becomes overripe. A strain harvested at peak potency that tests out at 23.5% THC and less than 1% CBD (cannabidiol) and CBN (cannabinol) may test out at 20% THC and more than 1% CBD and CBN harvested seven days past peak potency. This cannabinoid shift changes the character and intensity of the high, and usually not for the better.

Harvesting Mistake #5: Not Analyzing Psychoactive & Medical Goals

Many marijuana growers don’t realize marijuana harvesting timing helps determine the intensity and type of medical and recreational effects their buds give them. Harvesting too early when all resin glands are still intact, sturdy and clear provides a lighter, less-intense, more stimulating high than harvesting at peak potency when some of the resin glands are cloudy and/or amber.

Harvesting too late, when many of the resin glands are cloudy and/or amber and a significant number of glands are degraded, produces a heavier, couchlock, more numbing high.

You can get different types of recreational and medical effects from the same plant—depending on whether you harvest early, at peak potency, or overly late. So have you ever sat down and thought out exactly what kind of high you want from the marijuana you’re growing? Most growers haven’t. They grow their plants, harvest when they think the time is right, and accept whatever high they get.

Now you know you have a choice: harvest early for a speedier high, harvest late for a heavier high.

Marijuana Harvesting Mistake #6: Unsanitary Procedures & Tools

Marijuana plants can be attacked by spider mites, aphids, thrips, powdery mildew, gray mold and other baddies while they’re growing, but those attackers can hit during harvesting, drying, curing and storing cannabis too.

I’ve seen growers using the same pruners and trimming scissors to harvest many plants, without frequently dipping the implements in alcohol to sterilize them as marijuana harvesting continues. The lack of cleanliness can transfer pests and diseases from one plant or branch to another, creating an epidemic that damages the drying crop that still has plenty of moisture left in it to support insects, molds or fungi.

Marijuana Harvesting Mistake #7:  Drying Sites

Outdoor marijuana growers find it difficult to do optimum marijuana harvesting scheduling because bad weather, disease, pests, fires, police, and rippers can arrive suddenly and force a harvest on the grower. Outdoor marijuana growers might be relying on an outdoor drying shed, barn, or other site similar to what tobacco farmers use to hang their harvest long-term for drying and curing, but bad weather or invaders could take away the usefulness of that site.

Whether you grow outdoor or indoor marijuana, your buds do best with a climate-controlled, vented, odor-filtered room with the proper physical structures for hanging whole plants and drying racks for cut branches and buds. The room should have the proper temperature, humidity, air circulation and air venting that promote steady removal of moisture from buds.

I’ve seen many a grower harvest before they had a drying site ready. They piled their plants on top of each other, cut the buds off the branches and threw them in bags, or hung the plants from clothes lines in humid rooms with poor air circulation. All of these conditions degrade buds and can lead to storage molds and other problems.

When no optimum drying site could be found, I’ve seen professional growers trim their buds off branches, bag them and flash freeze them in deep freezers. The buds were sold to cannabis concentrates processors who used them to make frosin and other live resin concentrates that retain almost all the taste, flavor, psychoactive and medical potency of the growing bud.

Marijuana Harvesting Mistake #8: Not Enough Time & Personnel

Marijuana harvesting takes time. It can take less time if all you do is cut the main stalk at the base of each plant and hang the plant in a drying room. If you intend to cut branches or buds during harvesting instead of just hanging the whole plant, harvest effort and time is greatly increased.

Growers who run large indoor or outdoor marijuana gardens might not want to handle the entire harvest themselves. Then they run into the security risk of using friends, associates, or hirelings as marijuana harvesting helpers. Most of the time, those helpers want to be paid, which cuts into profits. And sometimes, those helpers steal part of the crop as they harvest it, or they could be security risks, or both.

Take a moment to analyze how much time and manpower you’ll need to do your marijuana harvesting, and plan ahead. I’m glad to spend three hard workdays harvesting all my plants myself rather than have anyone know I’m growing weed and create a potential security risk for me.

Cannabis Harvesting Mistake #9: No Flush

In the last 5-7 days before harvest, feed plants only 5.9 pH reverse osmosis water with flushing agent Flawless Finish in it. This purges contaminants from the crops, making them tastier and cleaner-burning.

Now you know the most common marijuana harvesting mistakes. Most marijuana growers have made at least some of these mistakes. But we always go for growing marijuana perfection by learning from our mistakes, and that’s what honors our marijuana season and plants the most.