Reeferman Genetics – Chapter 13 – Grow Top Shelf Buds

Once plants have reached a good stature, have lots of healthy roots and show no signs of stress or deficiencies they may be ready to “flip” into bud. Auto flowering cannabis genetics will begin to flower all on their own, even under continuous lighting. However, the vast majority of cannabis strains are short day plants, meaning they need twelve hours of uninterrupted darkness to initiate and maintain flowering and budding. This is also referred to as “reproductive growth”.

Following the model offered in this grow guide, established one gallon rockwool grown veg plants will be transferred from the 2’ X 4’ horticultural trays in the vegetative growth area to the flowering or bloom room, and placed in the 3’ X 6’ horticultural trays.

Use recommendations in Lighting, Nutrients & Fertilizers and Environmental Control chapters to ensure you are maintaining the optimal environment for your crop each step of the way identified here in our SOP (standard operating procedure)’s section.

 Transitional Growth

Initially, short day cannabis plants will continue to produce vegetative growth for the first few days to two weeks after changing the lighting cycle to 12 hours lights on and 12 hours of uninterrupted complete darkness. You will notice the number of blades per new leaf begin to decrease, and finally you will see reproductive growth emerging from what were once growth sites.

Most strains will double in size during these first two weeks when shifting from vegetative growth to early flowering. Once pea-sized flower structures have established, the plant can be said to be in flowering or early budding.

This big jump in growth can catch the grower off guard, plants can use a lot of water and nutrients while filling up space very quickly. Be diligent and stay on top of these increased demands, and you will be rewarded with lots of healthy flowering sites up and down the stems, your ticket to big yields of high quality.


During the first week, prune off the leaves from the lower third of the plants. They will be shaded anyways at this point. This helps improve air flow and flight penetration in the rapidly expanding plant canopy. This is essential for keeping plants healthy. Overcrowding creates pools of moisture on foliage where plants are touching; this is a gateway to foliar diseases.

You may see an explosion of “sucker shoots” during transitional growth. It’s a good idea to prune off lower spindly growth, allowing the plants to put their resources into the upper flowering sites that will receive more light and air. Removing spindly growth doesn’t hurt yield potential, it increases it. Following the lighting recommendations and plant spacing in this guide, you’ll typically want to have three to six main branches per square foot in your horticultural trays. Note that some strains want to have fewer larger buds and others will have more lateral buds, get to know your strains, and give them what they like.

Flowering & Peak Bloom

At this point, plants will slow vertical growth and the flowering sites will continue to swell, forming buds. If you started a crop from regular seeds, now is the time to identify and pull out male plants before they develop mature flowers and pollinate the crop, creating seeded bud.

Identifying Males & Hermaphrodites

It’s also a time to watch out for hermaphrodites, plants that are female with just a few male flowers. They should also be removed from the garden. Hermaphrodites are rare but they do happen. South East Asian cannabis genetics are often more prone to developing some male flowers on an otherwise female plant.

This may sound funny, but the easiest way to spot male flowers early is to look at the “crotch” of a branch where a side shoot meets the main upright stem) near the top of the plant. Female plants will develop a small bulbous “cat eye” shaped structure, two white hairs (stigma) will protrude. It helps to use a magnifying glass or zoom photo for easier identification, what you are looking for is very small.

Male flowers (also seen in hermaphrodites) will form early in the crotch as well. They too are very small, but distinct. Instead of a cat eye shaped structure, they are considerably rounder and tend to hang down instead of protruding upright. Imagine a Christmas tree bauble hanging down; that’s likely a male flower. It can take a little practice to catch them in the earliest stages. After three or four weeks from changing to the budding cycle the differences should be very easy to spot. It’s important to remove male plants and hermaphrodites away from the garden area before any of the flowers develop fully and open. It doesn’t take much pollen to make a lot of seeds in your buds.


At around the fourth week of flowering is the time to remove any excess foliage in most strains, especially indica dominant or Kush dominant strains. Sativas don’t usually have a lot of foliage to begin with and won’t benefit from leaf removal.

This step is kind of like tough love. There is a lot of debate amongst growers as to the efficacy of leaf removal and better yields. We aren’t here to debate anything, just say what we know works.

In repeated tests in a wide variety of gardens with different growers, we have found that removing most of the big “fan” leaves and opening up the plant canopy to stronger lighting at the budding sites increases yields by as much as twenty five percent growing indoors under lights. Additionally, there is more uniform quality from top buds to bottom buds. Shaded buds do not have the density or size that buds receiving strong light intensity and good air movement do.

Mid Flower Maintenance

At this point the crop has had some longevity. So, any small issues may be more noticeable or compounded. In most crop feeding programs this is the point where fertilizer levels are strongest. We recommend doing a light flush of the growing medium with pH adjusted (5.5 pH for rockwool) ¼ strength nutrient solution for an irrigation cycle or two. This helps to reduce any accumulated fertilizer residues in the growing media. Discard this solution following and mix a fresh reservoir following your feeding program.

Nutrient residues and impurities tend to build up over time and can impede nutrient uptake and hurt bud quality. Don’t overdo it either. Hydroponic plants respond very quickly to a light flush of the growing medium.

It may be a good idea to give a light foliar application of insecticidal soap and potassium bicarbonate at this time. This will hell to prevent and control any issues that may be surfacing. Follow the recommendations in this guide in our Pest Control chapter. BE EXTRA CAREFUL NOT TO SPRAY FLOWERS, JUST THE FOLIAGE. MAKE SURE AIR MOVEMENT FANS ARE OFF SO YOU CAN CONTROL SPRAY CONTACT

Crop Support

Buds can start to get top heavy by mid flowering. Some strains require additional support. Trellising using plastic netting is effective. Some growers start training their crop to grow through trellis net supports from early flowering. We recommend holding off on trellising as long as possible so that it’s easier to access all of the plants in your garden for important stuff like pruning or spraying.

If you used metal racking to support your horticultural trays, affixing plastic trellis netting is quick and easy, just a few zap straps around the uprights will usually hold netting taught and steady. Sometimes trellising in several layers may be necessary, i.e., taller crops.

Once the plants start growing through netting, simple practices can get more tedious. Being able to remove any individual plant for inspection or maintenance can be very helpful in producing healthier and higher yielding cannabis crops.

Ideally, your strain selection will have sturdy branches and won’t require additional support. However, this isn’t the first criteria to select a strain for, so sometimes trellising is a good practice.

Late Flowering & Ripening

At this point, vertical growth has halted, and buds are gaining mass and density and showing maximum resin production. Aromas and colorations also continue to become more pronounced. Water consumption decreases, as does the demand for nutrients. As the cannabis crop winds down, plants transfer stored nutrients into the buds, less is being taken up from external sources. Lower leaves begin to fade, yellow, and fall off, progressing upwards on the plants as they near peak maturity.

Major Mass

Towards the last one to two weeks before peak bud maturity, it may not look like anything new is happening. To the experienced grower, this is when the buds really take on some mass for a healthy harvest dry weight. If harvested too early, buds dry up considerably and may not retain much density. When harvested at peak maturity, there is more dry weight to the buds, and they retain a higher level of density after the dry and curing process. Additionally, waiting the extra days can add up to higher resin levels, which means more THC, CBD, and terpenes; all the stuff that makes a bud good.

Conversely, growers harvesting for extract only may not find the returns for waiting an extra week for peak maturity to be worth the time. Identify if you are growing the crop for buds or for extract, if for buds, go a little longer to get more of what you desire.

Identifying Peak Maturity

You should be observing earlier maturity in your buds than you may be accustomed to if following our recommendations with lighting, hydroponics, environmental control, and nutrients with good cannabis genetics, i.e., instead of harvesting at eight weeks your crop looks ready at six.

Hydroponic plants tend to stay more vibrant, even at the end of their peak life cycle versus soil grown plants, you could probably leave them for a lot longer and they will continue to make progressively smaller gains daily; they just want to keep going.

Bud Development

However, when new bud development all but halts you will see a swell or final push in the buds. Examine the structure and trichomes carefully. Trichomes are the hair like structures that cover the small leaves attached to buds. They occur in great abundance on the surface of the buds themselves (calyx, empty seed pods). Using a magnifying glass or zoom photo examine the heads of the trichomes on different heights up and down the plant.

Typically, as resin matures it changes opacity and or color. Milky white is usually preferable for a good balance of flavor to potency. As resins pass their peak, they begin to turn amber and eventually degrade and snap off the top of the trichomes.

Also examine the stigma, the “hairs” on the bud. At maturity there are very few white or pink hairs, they turn brown or red and dry up. Finally, the calyx (empty seed pods) on the buds can really swell up and get bigger. As you gain a feel for your plants you will notice the buds and remaining foliage feel tougher, thicker, and “leatherier”.

Ready to Harvest

Now your buds are ready to harvest, congratulations, you are most of the way there. Handling, trimming, and curing your harvest can make night and day differences in the quality of your buds. Characteristics like flavors, aromas and smoking quality can be enhanced and preserved with proper handling or lost with hasty inexperience. It pays to remain vigilant until buds are ready to smoke.


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