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by Grow Supply Shop Staff September 18, 2020 4 min read

Here’s What You Can Expect During Those Last 2 Weeks of Flowering

(If it’s not the final two weeks, let’s just pretend it is.)

Those trichomes (hairs) were once a clear color before becoming white and cloudy. Now they’re turning brown or amber.

The plants were once green. Now you’re seeing more yellow in the leaves. Some leaves may have already fallen off.

Some growers will tell you that the buds won’t grow any further and that it’s time to do your flushing. Others will say, “Now wait a minute! It ain’t over yet!”

Who’s right? That all depends on what you do and don’t do over the next couple of weeks.

To Flush or not To Flush?

If you’re not familiar with flushing, it is a process for removing nutrients and salts from the soil using pH neutral water. This allows the plants to focus on using up nutrient reserves.

  • Most growers flush daily for a few days to a week sometime during the final two weeks.
  • Advocates say it improves flavor and keeps the smoke less harsh and more flavorful. Nutrient build-up can create a harsher smoke.
  • Non-advocates say that flushing is only necessary if you’ve been overfeeding nutrients to your girls. They also say that some nutrient manufacturers recommend higher-than-necessary nutrient doses.
  • Recent research has stirred up a fierce debate on whether to flush.
  • RX Green Technologies, a nutrient company, organized a blind taste test in 2019.
  • They used four groups of Cherry Diesel plants. Each group came from a coco medium flushed for either zero, seven, 10, or 14 days.
  • Consumers and cannabis industry experts in the blind taste test actually preferred the smoke from the non-flushed group over the others.
  • Other findings: Yield, potency, terpene levels, and THC concentrations did not vary significantly between groups.

Whether you flush or not, there are techniques that are far more certain if you’re looking for fatter, stickier, and better-tasting buds. Stick around for those.

7 Tips for Maximizing Yield & Quality

1. Prune Those Leaves 

If you have two weeks until harvest and haven’t pruned yet, that’s fine. Chances are that some leaves turned yellow and fell off. That saves you some work.

Find the remaining yellow leaves and carefully remove them. They have served their purpose. Now they’re just energy drains. You want your girls to focus energy on producing flowers instead of maintaining leaves.

Pruning will free up that energy and also allow higher light exposure, especially for those bottom buds. 

2. Drop the Humidity

From the fifth week of flowering and onward, the ideal relative humidity is between 40% and 55%. Above that, the buds could become hard and moldy.

Lower humidity can alert the plants to protect themselves from dehydration and produce more trichomes. Trichomes produce the cannabinoids, resin, and terpenes.

If your grow is indoors, use proper ventilation methods to get rid of hot and moist air and bring in more CO2-rich air.

3. Drop the Humidity Even More in the Last 2 or 2 1/2 days

This is when a humidity between 25% and 32% is ideal. This technique is known to swell up the resin glands and multiply trichome production.

Growers use this trick for the above purpose and to help trigger a “Final Bud Swell” just before harvest.

The theory is that the lower humidity stops photosynthesis. Photosynthesis uses a lot of energy better spent on improving the size and quality of buds.

4. Drop the Light Hours, Too

During those final two days are so, you also want to change your light schedule. You want eight hours of light and 16 hours of darkness.

Between this and the humidity drop, this should trigger some major resin sack swelling. This may fatten the buds and boost the resin levels.

Some growers will do a 0/24 schedule for the final two days instead of the 8/16. That means zero light for 48 hours.

5. Stop the Nutrients

Whether you’ve been overfeeding the plants or not, it is common practice to stop adding nutrients during the last two weeks. Nutrient uptake may require a lot of energy. Most likely, there are plenty of nutrients in the growing medium and in the plants.

For hydroponic grows, you can wait until five days from harvest to yank the nutrients.

Some people will recommend adding a bloom booster during the last two weeks. This may only be helpful in special cases. Most likely, it will be risky.

6. Crank Up the Sugar (Molasses)

Plants use sugar for energy just like we do. They will use this energy during flowering to produce flowers. A little extra sugar can lead to bigger and stickier flowers.

Sulphur-free molasses is a common sweetener for grows. You can add it to feed water during the last few weeks of flowering. If you practice flushing, you can add molasses to the flushing water. Otherwise, add it to the feed water.

7. Know When to Harvest

Philosophies about the exact day to harvest vary. A delay of just a couple of days can make a big difference in the psychoactive effects of the buds.

A longer delay favors sedation. A shorter one favors more uplifting and energetic. Growers hoping for that Final Bud Swell may wait a few extra days as well.

Your trichomes were once crystal clear before taking on a cloudy white color. Two weeks out from harvest, that crystal clear is probably completely absent. Now, most are milky white and some are amber or brown.

Most growers harvest when 85% of the trichomes are white and 15% are brown.

This will favor that uplifting high. A 70% to 30% ratio is perfect for pain relief and sleep support.

Of course, your particular strain will have a say in that outcome. These are just rules of thumb.

 Are You Giddy Yet?

Now you really have something to look forward to! Just follow the tips above, and see what happens in those final two weeks before harvest. Let us know how it goes.
If you have any questions about your grow, call or text us at Grow Supply Shop. We're not only retailers. We are expert growers.
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Grow Supply Shop Staff
Grow Supply Shop Staff

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