Early blight is among the most destructive diseases in tomatoes. If it is untreated, you may end up losing the whole of your crop. Below are some of the compost teas which can help in treating early blight in tomatoes. The purpose or goal of these teas are;
- To Boost beneficial microbes
- Strengthen plant cell walls
What are Aerated Compost Teas?
Compost tea is a natural liquid fertilizer or biofungicide made by steeping compost in water, with or without the addition of air. The purpose is to extract beneficial microbes and soluble nutrients, and then provide them to plants in a form that they can readily uptake and utilize.
Production of quality compost is the most important step in making high-quality, beneficial compost tea. One article published by the organic eprints states that
The composition of any compost tea will be affected by the ingredients used to make it, e.g. woodchip has been shown necessary to increase the proportion of fungi in composts. Using only farm manure and green waste will tend to produce composts which are relatively low in fungi.
A balance between farm manure, green manure, and other materials like wood chips will increase the value of the tea.
Core Anti-Blight ACT (Aerated Compost Tea) Recipe (5-Gallon Brewer)
Note: Use the tea weekly from transplant through fruit set.
| Ingredient | Amount | Purpose |
|---|---|---|
| High-quality fungal compost (vermicompost + leaf mold) | 2.5 cups | Inoculum: Trichoderma, mycorrhizae |
| Unsulfured molasses | 1 tbsp | Bacterial food (B. subtilis) |
| Kelp meal | 2 tbsp | Potassium, trace minerals, stress resistance |
| Soluble silica (e.g., potassium silicate or AgSil-16) | 1–2 tsp | Strengthens cell walls, proven Alternaria deterrent |
| Fish hydrolysate (2-4-1) | 1 tbsp | Amino acids, chitin → chitosan (fungal inhibitor) |
| Non-chlorinated water | 5 gal | — |
Brewing Steps
- Pre-aerate water 1 hour to off-gas chlorine.
- Suspend compost in 400-micron bag
- Add all ingredients
- Stop pump
- Filter through 200-micron mesh to prevent sprayer clog
Application
- Dilute tea and water in the ratio 1:15
- Spray both sides of leaves in early morning
- Coat lower leaves first
- Reapply every 5–7 days or after heavy rain.
Emergency Knockdown Recipe (When Spots Appear)
Add these to the Core Recipe for 48 hr before outbreak.
| Add-In | Amount | Action |
|---|---|---|
| Neem seed meal | 1/4 cup | Azadirachtin disrupts fungal spores |
| Serenade® ASO (B. subtilis QST 713) or DIY B. subtilis culture | 1 tsp | Direct antagonist to Alternaria |
| Horsetail tea (Equisetum arvense) | 1 cup strained | Extra silica + antifungal compounds |
Non-Aerated Backup (No Brewer)
Quick 24-hour steep if ACT equipment fails.
- Mix 1 cup fungal compost + 1 tbsp kelp + 1 tsp silica powder in 1 gal water.
- Stir 2x daily; strain after 24 hrs.
- Dilute 1:10 and spray.
Pro Tips for Early Blight Control
| Strategy | Why It Works |
|---|---|
| Remove lower 12″ of leaves at transplant | Reduces splash-up of spores |
| Mulch heavily (straw/compost) | Prevents soil-to-leaf contact |
| Water at base only | Keeps foliage dry |
| Rotate crops 3+ years | Breaks disease cycle |
| Test spray on 1 plant first | Avoids phytotoxicity from silica |
Quick Spray Schedule
| Week | Action |
|---|---|
| 1 (transplant) | Core ACT spray |
| 2–6 | Weekly Core ACT |
| Spots appear | Emergency Recipe + prune infected leaves |
| Fruit set | Resume Core ACT every 7–10 days |
Conclusion
Aerated compost tea (ACT) emerges as a dynamic, living ally in the fight against early blight in tomatoes, harnessing a thriving community of beneficial microbes—especially Trichoderma and Bacillus species—to crowd out Alternaria solani while reinforcing plant resilience with bioavailable silica, potassium, and natural elicitors. Crafted through a 24–36-hour oxygenated brew using premium fungal-rich compost, restrained molasses, and strategic boosters like kelp and fish hydrolysate, ACT unleashes a targeted microbial army onto leaf surfaces, slashing disease pressure by as much as 60% in real-world trials.
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