Overview
This lecture explains how to use 3% hydrogen peroxide to manage fungal issues on tomato (and pepper) plants, covering identification, mixing ratios, application routines, and considerations for different plant types.
Identifying Fungal Issues
- Fungal problems commonly seen are septoria leaf spot and early blight in tomato plants.
- Early fungal signs: small brown dots with yellow halos on leaves.
- Brown circles, sometimes with concentric rings and yellow halos, are typical fungal patterns.
- Not all yellowing or dying leaves are caused by fungus; check for patterns across multiple plants.
Hydrogen Peroxide Application - Maintenance
- Use 3% hydrogen peroxide at 4–6 ounces per 1 gallon (3.8 L) of water for routine care.
- Spray leaves (tops and undersides) every 10–14 days for maintenance.
- Always test spray on a few leaves and wait 48 hours to check for damage before full application.
- Make only as much spray as needed; use immediately as hydrogen peroxide loses effectiveness over time.
Hydrogen Peroxide Application - Outbreak
- For fungal outbreaks, increase to 6–8 ounces per 1 gallon of water.
- Spray every 3 days, for 3 cycles (total of 3 applications).
- After outbreak management, return to routine maintenance spraying.
Additional Tips & Plant-Specific Notes
- Hydrogen peroxide cleans leaves but does not remain on them to prevent future fungus.
- Other antifungal sprays like baking soda or wettable sulfur stay on leaves and prevent future fungal attachment.
- Consistent spraying schedule is more important than frequency; adapt to personal time constraints.
- Use the same 4 ounces/gallon ratio for pepper plants; spray only if fungal patterns are seen.
- Determinate tomato varieties naturally die off after fruiting; some leaf yellowing is normal, but still spray for potential fungus.
Key Terms & Definitions
- Hydrogen Peroxide (H2O2) — A chemical compound with two hydrogen and two oxygen atoms, used here for cleaning plants of fungus.
- Septoria Leaf Spot — A common tomato fungal disease presenting as small brown spots with yellow halos.
- Early Blight — Another fungal disease in tomatoes, often appearing later in the season.
- Determinate Tomatoes — Varieties that grow to a set size and then stop, with a single large fruit set.
- Indeterminate Tomatoes — Varieties that grow and produce fruit continuously throughout the season.
Action Items / Next Steps
- Identify any fungal patterns on your tomato and pepper plants.
- Prepare and test hydrogen peroxide spray as described before full application.
- Establish a routine spraying schedule based on garden needs and time availability.
- Watch the recommended video (if available) for further help with fungal pattern identification.