Hydro CBD flowers: three references compared, figure by figure

Hydroponics is growing without soil. The roots develop either in a circulating nutrient solution or in a chemically unreactive support that the grower irrigates: rockwool, clay pebbles, perlite, coco fibre. What is steered is pH, the electrical conductivity of the solution, its temperature and the light level. The FAO devotes a whole chapter of its greenhouse good-practice manual to it, headed "Soilless culture".

Two practical consequences follow. First, hydroponics is a growing method, not a label: it prejudges neither the cannabidiol content, nor the terpene profile, nor the absence of residues, three points that are read on the batch certificate. Second, the border between "soilless" and "hydroponics" is a matter of definition: an indoor crop on coco-perlite is indeed a crop without soil, and the agronomic literature ranks it among soilless systems, but a grower who does not write the word has not claimed it.

A third consequence holds for the legal framework: the substrate has no bearing on legal status. The arrêté du 30 décembre 2021 (the French ministerial order on hemp) governs the variety sown and the plant's tetrahydrocannabinol content, which is no higher than 0.30%; the Conseil d'État decision of 29 December 2022, no. 444887, annulled the ban on selling raw flowers. Neither text says anything about the growing medium. The three main growing methods are compared in our guide to indoor, outdoor and greenhouse.

The left-hand column repeats the page's wording, word for word.

The count leaves no room for argument: one page claims hydroponics, four a soilless crop on coco-perlite, one an indoor crop with no further detail, three a greenhouse and five the open field. Nine pages out of fourteen therefore describe a crop in soil, under glass or in a field, the opposite of what the word leads you to expect.

Two details can be added. The displayed name keeps "Hydro" on only one page, Bubble Gum Hydro; elsewhere the word lives in the address alone. And on the Purple Runtz page, the description speaks of an "indoor crop, no growth regulator" while the editorial section further down writes hydroponics: the page says both, the second wording being the more precise.

Only three pages describe a soilless crop with enough precision to be compared. The other eleven are set aside, with no judgement on their quality.

Purple Runtz, batch PG-26-DA5E. The only page to write the word: its editorial section describes a crop "on an inert substrate irrigated with a nutrient solution", under controlled light, and its FAQ answers the entry "What does hydro mean" with the hydroponic definition. HPLC panel: 10.8% CBD, 0.6% CBDA, 0.4% CBG, 0.1% Δ⁹-THC. An earthy, spicy profile, carried by myrcene.

Bubble Gum Hydro, batch PG-26-5045. Its description writes an indoor crop on a coco-perlite substrate, controlled photoperiod, no synthetic pesticides. It is soilless, but the page never uses the term hydroponics: it is therefore presented here as soilless. HPLC panel: 10.8% CBD, 1.1% CBDA, 0.4% CBG, 0.1% Δ⁹-THC. A lemony, zesty profile, dominated by limonene; opaque glass, storage between 10 and 20 °C.

Orange Fritter, batch PG-26-FF08. The same growing wording, even though the displayed name has lost the "hydro" mention. HPLC panel: 11.3% CBD, 0.6% CBDA, 0.6% CBG, 0.2% Δ⁹-THC. A woody, resinous profile, marked by β-caryophyllene; humidity held between 55 and 65%.

The last line is a division, not an estimate. At 100 g, Purple Runtz works out at €2.05 per gram of material and assays at 10.8%: 2.05 ÷ 0.108 = €18.98 per gram of cannabidiol. Bubble Gum Hydro shares the same price and the same content, so the same result. Orange Fritter assays higher but costs more: 2.40 ÷ 0.113 = €21.24. At the first tier, 7.95 ÷ 0.108 = €73.61 against 8.95 ÷ 0.113 = €79.20. Orange Fritter's extra 0.5 point of CBD therefore does not make up for its €0.35 gap per gram.

The three pages show the same arrangement, run by a third-party laboratory under ISO/IEC 17025 accreditation: cannabinoids by HPLC, terpenes by GC-MS, pesticides by LC-MS/MS, heavy metals by ICP-MS. The certificate downloads from the "Batch" line. Four checks are enough: the batch number on the certificate must be the one shown on the page; Δ⁹-THC must be quantified and stay below 0.30%, here 0.1%, 0.1% and 0.2%; the report date must be later than the stated harvest; and the variety name must appear in the common catalogue.

What the certificate does not say is the growing method: no analytical method distinguishes a hydroponic flower from an open-field one by its cannabinoid profile. The set-up remains a grower's declaration, to be read where it is written. And a page name is not data: the "hydro" segment serves here to tell apart two batches of the same line, as with Purple Runtz and its namesake without the suffix.

Three elements stay comparable everywhere: the measured content with its batch number, the price at the tier chosen, and the storage conditions, a flower's stability depending more on how it is kept than on its substrate; see our article on storing flowers. For the smaller calibres, which come from the same batches, see the small buds guide. None of these flowers is a foodstuff: they are sold to adults, with no property claimed, as the FAQ points out.

• Phytogrammes, Purple Runtz page, batch PG-26-DA5E (hydroponics mention, HPLC, price by tier)
• Phytogrammes, Bubble Gum Hydro page, batch PG-26-5045 (coco-perlite growing, HPLC, storage)
• Phytogrammes, Orange Fritter page, batch PG-26-FF08 (coco-perlite growing, HPLC, humidity)
• Phytogrammes, Wedding Cake page, batch PG-26-3E83 (open field despite the address)
• Légifrance, arrêté du 30 décembre 2021 (authorised varieties, 0.30% threshold)
• Conseil d'État, decision of 29 December 2022, no. 444887
• FAO, "Good Agricultural Practices for greenhouse vegetable crops", chapter 12, soilless culture
• European Commission, plant variety catalogues and databases
• ISO/IEC 17025, requirements for testing and calibration laboratories