Organic Foliar Spray
Low-toxicity foliar sprays for home gardens and organic-certified farms.
Organic sprays are almost always contact-only, meaning coverage matters more than the product itself — both leaf surfaces need to be wetted for the spray to work at all. They suit home gardens and certified-organic operations where synthetic fungicides aren't an option.
Step-by-step protocol
- Dissolve 5 g potassium bicarbonate + 2 mL horticultural oil in 1 L water.
- Spray both leaf surfaces early morning or late afternoon.
- Repeat every 7 days during outbreak, up to 3 applications.
- Alternate with 1% neem oil for pest suppression.
Frequently asked questions
Are organic sprays as effective as synthetic fungicides?
Potassium bicarbonate has matched conventional fungicides against powdery mildew in university trials, but most organic sprays need more frequent reapplication since they break down faster and only work on contact.
What time of day should I spray organic treatments?
Early morning or late afternoon, to avoid leaf burn from sun on wet foliage and to reduce exposure to pollinators that are most active midday.
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