DIY Bordeaux Fungicide: Recipe, Preparation, and Application Tips

Bordeaux mixture (copper sulfate, hydrated lime, water) controls fungal diseases (downy/powdery mildew, black spot) and bacterial issues (fire blight) during dormancy. Apply in fall/winter for spring protection.

Standard Recipe (10-10-100)

10 parts copper sulfate : 10 parts hydrated lime : 100 parts water.

Preparation Steps

1. Dissolve 1 lb copper sulfate in 1 gal water (slurry in sealed jar).
2. Mix 1 lb hydrated lime in 1 gal water; let stand 2+ hours.
3. In a bucket, combine 2 gal water + 1 qt copper solution + 1 qt lime solution. Stir as adding lime.
4. Use immediately—mixture doesn’t store.

Small-Batch Version

1 gal water + 3⅓ tbsp copper sulfate + 10 tbsp hydrated lime. Agitate well before spraying.

Important Notes

• Wear dust mask when handling lime.
• Leaves blue-green stain—avoid near houses/fences.
• Not compatible with pesticides; corrosive to equipment—rinse thoroughly after use.
• Use lime from current season only.

Test on a small plant area first. Apply on dry, cloudy days to prevent leaf burn.