Open Source Apothecary At Home / The twelve-month course

Unit 7 (July): Midsummer — harvesting at peak

The month the harvest-timing principle becomes something you can smell.

guide

This unit is the practical core of the whole course. Harvest timing is the most reproducible finding in the cultivation literature: the content and composition of a plant's active compounds change with developmental stage, with season, and with time of day.

Why midsummer. Most flowering-top herbs peak at full flower, which is July here — St John's wort, yarrow, lavender, and the second flush of many leaf herbs. Composition shifts across the flowering period, which is why "harvest at full flower" is a stage rather than a date, and why a rule tied to the calendar will be wrong in half of years.

Time of day. Volatile-oil content varies diurnally. The convention is mid-morning, after the dew has dried and before the heat, and the reasoning is sound in both directions: damp material moulds, and hot material has already begun losing volatiles.

Drying is where beginners lose the harvest. Aromatic material is dried cool, in shade, with moving air — heat drives off exactly the compounds you grew the plant for. Root, bark and seed are dried warm, 45-55 C, because there are no volatiles to protect and there is a real mould risk. The two regimes are not interchangeable, and applying the wrong one is the most common way a good harvest becomes brown leaf.

The dryness test. Leaf crumbles, stems snap, root snaps. Then jar a sample and check it the next day — condensation inside means it was not dry enough, and that is the check that catches the mistake while it can still be fixed.

St John's wort carries the month's safety lesson — the longest drug-interaction list in the pharmacopoeia, and photosensitising.

What the studies found

Growing it

In season: full flower

| Plant | Part | Timing | |---|---|---| | St John's wort | Flowering tops | Full flower — the red oil is made now | | Yarrow | Flowering tops | Full flower | | Lavender | Flower spikes | Just as the flowers open, before full open | | Calendula | Flowers | Continuing daily | | Mint, lemon balm, sage, thyme | Leaf | Cut back after flowering for a fresh flush |

Cut in dry conditions, mid-morning, into a breathable basket. Never a sealed bag.

Take no more than a third of a plant's top growth, and leave the strongest plants to seed.

Preparation

Project: the midsummer drying run, and St John's wort red oil

Set up drying properly

• Aromatics: dark, dry, ventilated, moving air, ambient temperature. A small fan transforms results in a humid climate.
• Roots, bark, seed: 45-55 C, sliced, single layer
• Turn gently every day or two

St John's wort red oil

• Fresh flowering tops, packed into a jar, covered with olive oil
• Leave in sunlight 3-6 weeks, shaking daily, until the oil turns deep red
• The colour change is the hypericin extracting — it is the visible endpoint
• Strain and bottle in amber glass; for topical use on nerve pain, bruises and wounds

The dryness check that matters

• Jar a sample of each batch and inspect it the next day
• Condensation inside means return it to drying

Label everything: plant, part, date, place. This month generates more jars than any other.

Cautions and interactions

• St John's wort interacts with a very long list of drugs and can make them stop working.
• Do not combine St John's wort with an SSRI — serotonin syndrome risk.
• St John's wort is photosensitising — avoid high sun exposure while taking it.
• Do not dry aromatics in an oven, a hot car, or direct sun.
• Do not store under-dried material — mould carries mycotoxins. Discard rather than salvage.

When this is not a self-care problem — get help

• Unplanned pregnancy while relying on a hormonal contraceptive — speak to a clinician.
• Severe sunburn or a skin reaction after starting St John's wort — stop and get assessed.
• Any jar showing condensation, mould or a musty smell — discard the whole jar.

Related

• The twelve-month course
• Harvesting at the right moment
• Drying and storing so the potency survives
• St John's wort
• Oil infusions, and turning them into salves

Sources

1. The efficacy and safety of St. John's wort extract in depression therapy compared to SSRIs in adults: A meta-analysis of randomized clinical trials. Advances in clinical and experimental medicine : official organ Wroclaw Medical University 2023; doi:10.17219/acem/152942 PubMed 36226689
2. The Efficacy of Saffron in the Treatment of Mild to Moderate Depression: A Meta-analysis. Planta medica 2019; doi:10.1055/a-0660-9565 PubMed 30036891
3. Antidepressants for smoking cessation. The Cochrane database of systematic reviews 2014; doi:10.1002/14651858.CD000031.pub3 PubMed 24402784
4. Escitalopram versus other antidepressive agents for depression. The Cochrane database of systematic reviews 2009; doi:10.1002/14651858.CD006532.pub2 PubMed 19370639
5. Milnacipran versus other antidepressive agents for depression. The Cochrane database of systematic reviews 2009; doi:10.1002/14651858.CD006529.pub2 PubMed 19588396
6. St John's wort for depression. The Cochrane database of systematic reviews 2005; doi:10.1002/14651858.CD000448.pub2 PubMed 15846605