Cosmos F1 Grow Report: Week-by-Week Diary

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Key Takeaways

• Cosmos F1 is Royal Queen Seeds’ first true F1 CBD cannabis variety, combining very high CBD, just 0.5% THC, strong sativa structure, and consistent autoflowering performance.
• This real grow report follows Cosmos F1 from germination to harvest, tracking watering, pH, nutrients, height, environment, flowering progress, and final results week by week.
• The plant finished in 68 days from sprouting, reaching around 74cm in height and producing 69g of dry flowers in a shared indoor tent.
• Once cured, Cosmos F1 delivered crisp pine, creamy cookie, and peppery flavors alongside a clear, meditative, non-intoxicating CBD effect.

Cosmos F1 stands out as a notable entry in the CBD category, and this grow report keeps the focus on her performance from start to finish. Built from real GrowDiaries data, it tracks the details that matter in a practical home grow: plant height, watering volume, pH, nutrient mix, and how the environment shifted at each stage. This is a real-world Cosmos F1 grow report, not a breeder summary, so you can follow the run one week at a time.

Strain Overview: What Cosmos F1 Brings to the Grow Room

Cosmos F1 earned a place in this run because she brings something new to the F1 lineup. She is Royal Queen Seeds' first true F1 CBD cannabis variety and also the largest autoflowering cultivar in the entire F1 range. Her genetics trace back to a pure inbred line of CBD Oregon, which shows up in her strong sativa character, tall and upright Christmas-tree structure, long and airy flowers, and bright green leaves. Because both parent lines were inbred for stability before the cross, this variety produces a highly uniform crop, with plants reaching a similar height, moving through the same timeline, and delivering a consistent cannabinoid profile across the grow.

THC comes in at just 0.5%, while CBD is listed as very high. She is an autoflowering variety with a flowering window of 45–55 days and an expected harvest in 75–85 days from germination. Indoor yields are rated XXL, and her expected height falls between 2.3–3.3 ft. The terpene profile is led by myrcene, farnesene, limonene, pinene, and caryophyllene, bringing crisp pine, creamy cookie depth, and a distinct peppery edge. The expected effect leans clear and meditative, with physical relaxation, body ease, and no mental fog.

My Grow Setup on the Farm

This was a compact indoor run in a small shared tent, with no training, no transplants, and no interventions beyond watering, feeding, and basic environmental control.

Grow Space and Equipment

• Grow Box: Secret Jardin DS120W, 4 x 2 x 6 ft
• Lights: MIGRO 200+, upgraded to MIGRO Aray 4 during Week 1, kept around 14 in above the canopy
• Ventilation: TT Silent-M 100
• Filter: Primaklima PK 100/125
• Fans: Oscillating Koala Fan x 2
• Humidifier: Beurer LB 45
• Soil: BioBizz All-Mix in 3 gal Air Pots, amended with Easy Boost, Trichoderma, and seaweed
• Pots: 3 gal Air Pots
• Seeds: Royal Queen Seeds, Cosmos F1
• Nutrition: RQS Organic Nutrition, CalMg; Bio Flowering Booster (Bigger Flowers, Thicker Flowers, Sweeter Flowers); SuperVit drops

Growing Method and Starting Conditions

The seeds were germinated directly in their final pots to avoid any transplant stress. Before planting, the BioBizz All-Mix was built up in layers: Easy Boost Organic Nutrition pellets first, then seaweed, then a light addition of Trichoderma near the top. Once each pot was mixed and fully soaked, the seeds were placed in, and the water was adjusted to pH 6.0 from the very first irrigation. One Cosmos F1 seed went into the center of the tent, while two Orion F1 seeds filled the remaining spaces.

Germination (Sprout Days 1–5)

With the soil mixed and settled, all three pots went into the grow box with the humidifier running from day one. By day 3, the surface had dried slightly, so the top layer got a light watering to keep it moist without saturating the entire pot. On day 4, Cosmos F1 broke the surface at the same time as both Orion F1 plants, giving a clean and even emergence with no delay. By day 5, each plant received its first full watering, 17 fl oz at pH 6.0.

Week 1 Vegetation (Sprout Days 5–12)

Vegetative growth starts once a seedling has at least four true leaves. Cosmos F1 reached that stage around sprout day 5, measuring 2 in, with even leaf spacing and a compact, upright structure. The next day, all three plants were watered lightly with a total of 102 fl oz, keeping volumes modest while the roots established.

By sprout day 11, CalMg was added at 1 tsp per gal as a preventive measure. That change came from earlier runs where deficiency symptoms showed up when it was left out. The MIGRO Aray 4 also arrived that day and replaced the MIGRO 200+. The improvement in light spread across the full canopy was visible right away. Total irrigation was 203 fl oz, with CalMg at 1 tsp per gal and pH set to 6.0.

By sprout day 12, Cosmos F1 measured 3 in. She was still smaller than the Orion F1 plants sharing the tent, but her growth was steady and clean. A slower start did not translate to a weak plant.

Week 2 Vegetation (Sprout Days 12–19)

Week 2 began with a switch to an 18/6 light cycle. Cosmos F1 handled it well, adding almost 4 in over the week and finishing at 7 in, with a bushy, well-branched structure already showing the sativa frame underneath. She remained shorter than the Orion F1 plants, but her growth stayed even and confident.

Watering settled into a rhythm every 3–4 days. CalMg stayed at 1 tsp per gal, and Bigger Flowers from the RQS Bio Flowering Booster line was added once during the week as early flowering support. The medium moved through wet and dry cycles naturally, and the plant's water uptake stayed predictable.

Week 3 Vegetation and Entry into Flowering (Sprout Days 19–26)

By the end of Week 3, Cosmos F1 had moved into the flowering phase. Her structure was clearly sativa-leaning, with upward-reaching branches, tight node spacing in the lower section, and a central stem that was becoming more defined. The feeding program stepped up with Thicker Flowers added as a PK booster alongside CalMg and Bigger Flowers, plus two drops of SuperVit in one watering. Water volume increased to about 237 fl oz per session across the three plants, roughly 78 fl oz each, every 3–4 days.

Early in the week, the mix was 237 fl oz of water with 7 ml CalMg, 7 ml Bigger Flowers, and 3.5 ml Thicker Flowers at pH 6.0. A few days later, the same volume was used with CalMg only and two drops of SuperVit.

By the end of this stretch, the first pistils were unmistakable: white, delicate hairs at the nodes, the earliest clear sign that flowering had properly begun. In a CBD strain, that moment stood out.

Week 1 Flowering (Sprout Days 26–33)

By the end of the first week of flowering, Cosmos F1 stood at 21 in, a jump of almost 10 in in seven days and the biggest stretch of the entire cycle. The Christmas-tree structure was now fully visible, with a defined central cola forming above progressively lower branch tiers, each already carrying clusters of developing flowers. Dark green fan leaves looked healthy from top to bottom, no canopy management was needed, and she still had comfortable headroom inside the 6 ft tent.

Watering continued every 3–4 days at 237 fl oz for the tent, with pH held at 6.0 and CalMg, Bigger Flowers, and Thicker Flowers as the core mix. The medium was drying back cleanly between sessions, and the plant's water uptake stayed consistent.

Week 2 Flowering (Sprout Days 33–40)

Week 2 of flowering was steady. By the end of it, she measured 26 in, a gain of about 5 in as vertical growth began tapering toward her final height. The flowers were still in early formation, more framework than mass, but their spacing along the main stem and each side branch made the developing yield potential easy to see. Leaf color stayed strong, no deficiency symptoms appeared, and the same 237 fl oz every 3–4 days rhythm continued with CalMg and Bio Flowering Booster throughout.

The aroma was starting to show. At first it was faint, just a trace of pine when the tent opened, but it was clearly there. Something fresh and clean was coming through, with a creamy note building underneath. The terpene profile was beginning to take shape.

Week 3 Flowering (Sprout Days 40–47)

Vertical growth was slowing now, with the plant shifting energy into flower production instead of height. Early in the week, watering was 237 fl oz with 7 ml CalMg, 7 ml Bigger Flowers, and 3.5 ml Thicker Flowers at pH 6.0. A few days later, the same volume was given with CalMg only, plus two drops of SuperVit. At the end of the week, photos were taken and measurements were recorded.

Cosmos F1 stood at 29 in, about 2 in taller than the previous week and clearly nearing her limit. The main cola dominated the center of the canopy, while the side branches spread out in well-spaced tiers below it, each one packed with developing flower sites framed by healthy, dark green foliage. At 29 in, she was still comfortably inside the tent and well below the lights. This was the week the theoretical promise of F1 uniformity became something visible and tangible.

Week 4 Flowering (Sprout Days 47–54)

Vertical growth slowed as the plant committed fully to flower production, topping out at around 30 in. Density increased, resin started to build, and the first real stickiness showed up on the calyxes. Watering shifted to a consistent every-three-day schedule as demand rose with the increasing flower mass.

Cosmos F1 showed more leaf yellowing than her Orion F1 tentmates this week. The lower leaves in particular began to pale, an early sign of potassium deficiency, so adjustments were made to support her. The affected leaves were removed as symptoms developed.

Thicker Flowers, one of the three parts of the Bio Flowering Booster range, also works as a PK booster, so it was used to raise potassium levels: 237 fl oz with 7 ml CalMg, 6 ml Bigger Flowers, and 10 ml Thicker Flowers at pH 6.0. The same mix was repeated a few days later. Toward the end of the week, yellow leaves were removed before photos were taken. The flowers looked excellent, dense and sticky, with an aroma that pushed through even with the filter running. The peppery caryophyllene note had come through clearly alongside the pine, with a sweet, creamy layer building underneath.

Week 5 Flowering (Sprout Days 54–61)

The final nutrient feeding of the cycle came early this week: 237 fl oz with CalMg and Bio Flowering Booster at pH 6.0. A few days later, only plain water was given, 237 fl oz at pH 6.0. Photos were taken at the end of the week.

Cosmos F1 had turned noticeably yellow, with the leaves drawing back every remaining resource before the plant finished. All affected leaves were removed. The flowers told the more important story: trichome-heavy, firm, and compact at the top of the main cola and at the ends of every side branch, with slightly puffier lower sections that were still well covered in resin.

Trichome checks under the microscope started at this stage. Most trichomes were milky, with a small number beginning to turn amber. Harvest was close.

Week 6 Flowering and Harvest (Sprout Days 61–68)

Plain water every three days, with no nutrients added. The plant was finishing on her own reserves, with calyxes swelling slightly, resin thickening, and the tent aroma becoming impossible to miss.

Daily trichome checks confirmed the harvest window was open by sprout day 68: mostly milky heads, with a portion turning amber. The final plain watering came two days before chop to help the plant use up some internal moisture and lower the risk of mold during the early drying stage.

On sprout day 68, Cosmos F1 was harvested. The buds were firm and sticky across most of the canopy, with heavy trichome coverage all the way down to the lower flower sites. For a first CBD grow, she finished exactly as expected: precise, predictable, and clean.

Drying and Final Results

Cosmos F1 was hung whole in the grow box and dried in darkness for about 10–14 days with ventilation turned down. Once the outer buds felt dry and the smaller stems snapped cleanly, the flowers were trimmed and moved into jars. The aroma settled nicely during curing, with the pine sharpening, the cookies-and-cream depth becoming more consistent, and the pepper note coming through clearly on the exhale.

Total lifecycle: 68 days from sprout. Germination took about 3–4 days before the seedling broke the surface, putting the full seed-to-harvest timeline at roughly 71–72 days. The breeder's stated window is 75–85 days from germination, and while this run finished slightly ahead of that range, the trichome profile at harvest confirmed the plant was fully mature and ready. Final height was about 29 in, after peaking at 30 in late in flower. Final dry yield came to 2 oz from one plant.

For a single plant sharing a 4 x 2 ft tent with two others from start to finish, that was a strong result. She stayed within the expected height range and backed up the XXL yield rating under real growing conditions.

Genetic Attributes and History

Cosmos F1 descends from a pure inbred line of CBD Oregon genetics, which gives her the pronounced sativa structure, the long, wispy flowers, and very high CBD with negligible THC. What sets her apart from conventional CBD varieties is her F1 hybrid status. Both parent lines are stabilized through generations of inbreeding before being crossed, and the resulting first-generation offspring are remarkably consistent: plants in this variety reach a very similar height, flower on the same schedule, and deliver a highly uniform cannabinoid and terpene profile across the crop. There are no major outliers and no phenotype variation to manage. In a CBD strain, where consistency is the main goal, that is exactly what you want.

Flavor and Effects

Once cured, the terpene profile came through clearly. The dominant note is crisp pine, clean and sharp on the nose, with a fuller, almost creamy layer underneath that recalls modern Cookies-adjacent varieties, plus an unmistakable peppery bite on the back end from caryophyllene.

The effect is clear and meditative. With just 0.5% THC and very high CBD, there is no intoxication, no fogginess, and no couch lock. Instead, the experience leans toward physical ease paired with a focused, settled mental state. Cosmos F1 is especially well suited to growers who prefer high-CBD, low-THC varieties for daily use and value the clear-headed, functional quality that comes with a near-zero THC profile. For daytime sessions, she sits comfortably in the background. Not a reset, but an alignment.

What This Grow Taught Me

Trust the F1. Cosmos F1 grew exactly as described, hit her harvest window cleanly, and finished at a height and yield that closely matched the product specs. No major corrections were needed, no late adjustments, and no phenotype-hunting. Keep CalMg consistent, water thoroughly, let the pot dry back between sessions, and let the plant do what F1 genetics are built to do. The rest largely takes care of itself. That is the kind of honest grow reporting every diary should deliver.