For this Ortho fungicide concentrate, dilute 2–3½ teaspoons per gallon of water based on plant type, then spray to full leaf coverage.
Here’s a clear, field-tested way to prepare and apply this garden fungicide so you get solid coverage, steady control, and fewer do-overs. The rates below come straight from the product label, trimmed into quick steps you can follow with a hose-end or tank sprayer.
Mixing Ortho Max Concentrate For Common Crops
Rates vary by plant group. Use the table below to set your baseline. The numbers shown are teaspoons of concentrate per gallon of water, plus how often to spray when disease pressure is present.
| Plant Group | Mix Rate (per gal) | Spray Interval |
|---|---|---|
| Cucumbers, Melons, Pumpkins, Squash | 2 tsp | Every 7 days while risk remains |
| Tomatoes | 2 tsp | Every 7 days while risk remains |
| Potatoes | 1½ tsp | Every 5–7 days during active disease |
| Onion (Green), Leek, Shallot | 2½ tsp | Every 7 days; max seasonal label limits apply |
| Onion (Dry Bulb) & Garlic | 2½ tsp | Every 7 days; see harvest wait below |
| Roses | 1 Tbsp | Every 7–14 days based on pressure |
| Other Ornamentals | 2 tsp | Every 7–14 days based on pressure |
| Pachysandra | 3½ tsp | Every 7–14 days based on pressure |
| Conifers (Pine, Douglas-fir, Spruce) | 5 tsp per 4 gal | Every 21 days in seed beds until dry weather returns |
What You Need Before You Start
- Clean tank or hand sprayer with a working nozzle that produces a fine, even fan.
- Measuring spoons. Keep these dedicated to garden use.
- Fresh water supply.
- Gloves, long sleeves, long pants, and closed shoes. Add eye protection when mixing.
Step-By-Step Mixing Directions
1) Shake, Then Measure
Shake the bottle well. Measure the label rate for your plant group from the first table. Stick with teaspoons unless the label calls for tablespoons.
2) Fill Halfway, Add Concentrate, Then Top Up
Fill the sprayer halfway with water. Add the measured concentrate. Swirl the tank. Top up with water to your final volume. This sequence helps blend the suspension and reduces clumping.
3) Agitate Often
Give the tank a shake before you start and every few minutes while spraying. This fungicide is a suspension; steady mixing keeps the active ingredient evenly distributed.
4) Spray To Coverage
Coat the tops and undersides of leaves, stems, and fruit clusters until the surface looks evenly wet without heavy runoff. Uniform coverage is what delivers control with contact fungicides.
When To Make The First Pass
Start early. Begin at the first true leaf stage on vine crops, at 6 inches tall on potatoes, or at the first hint of conducive weather. For ornamentals, begin at spring bud break or new leaf emergence, then follow the schedule tied to each plant group.
Harvest Wait Times (Preharvest Intervals)
Many edible crops can be treated close to harvest, while a few need a longer wait. Use the chart below to stay on the right side of food-safety rules.
| Crop | Days To Harvest | Notes |
|---|---|---|
| Cucumbers, Melons, Pumpkins, Squash | 0 days | Spray stop once fruit has full, even coverage |
| Tomatoes | 0 days | Keep intervals tight in warm, humid spells |
| Potatoes | 0 days | Begin at 6 inches tall or first disease sign |
| Onion (Green), Leek, Shallot | 14 days | Do not exceed seasonal application limits |
| Onion (Dry Bulb) & Garlic | 7 days | Follow bulb-crop schedule through sizing |
Calibrating Your Sprayer
Good control rides on consistent output. Time your sprayer over a small, known area. For many home beds, one gallon covers about 200 square feet when you spray to a light glisten. If your output is heavier or lighter, adjust your walking speed or nozzle setting and recheck.
Coverage Tips That Prevent Misses
- Leaf undersides count. Tilt the wand and sweep upward for a quick pass beneath the canopy.
- Work in calm air. A light breeze scatters fine droplets and thins coverage.
- Do not spray wilted plants or during the hottest part of the day.
- Recoat after strong rain. Dry films can wash away.
Mixing Ortho Max Concentrate With Other Garden Sprays
This fungicide may be tank-mixed with select home-garden insecticides on ornamentals when both labels allow it. Keep the rate of each product the same as if you sprayed them alone. Add water first, then fungicide, then the partner product, with light agitation between steps. Skip more than three consecutive combined treatments; alternate with solo fungicide passes.
Safety, Re-Entry, And Cleanup
Personal Protection
Wear gloves, long sleeves, and eye protection while mixing and spraying. Wash exposed skin with soap and water after you finish. Launder work clothing separately.
Pets And People
Keep everyone off the treated area until the spray has dried. This window is usually a few hours under warm, dry conditions.
Rinse And Store
Triple-rinse the sprayer: add clean water, shake, and spray onto the treated area. Repeat twice. Store the concentrate in its original container with the cap tight, away from kids and pets, at room temperature. Avoid freezing and direct sun.
Diagnosing Common Diseases This Product Targets
The active ingredient shields foliage against a wide slate of leaf spots, blights, rusts, and mildews. A quick symptom guide helps you decide when to start or tighten the schedule.
Blights On Tomatoes And Potatoes
Look for dark, water-soaked lesions that spread fast in cool, damp weather. Start preventive sprays as the forecast shifts wet and keep intervals tight during outbreaks.
Powdery Mildew On Roses And Squash
Watch for white film on leaf surfaces. Begin early when daytime-nighttime swings widen. Good airflow and even leaf coverage keep it in check.
Downy Mildew On Cucurbits
Yellow patches on top, gray fuzz below. Start at first detection in your area and maintain weekly passes while conditions favor spread.
Label-Smart Best Practices
- Do not exceed the number of seasonal applications listed for each crop.
- Space sprays closer together under heavy pressure or frequent rain.
- Rotate with other fungicide groups across the season when your garden plan allows.
- Keep spray off water features and storm drains; sweep hard surfaces back onto soil.
Quick Rate Examples For Home Beds
Case A: 1-Gallon Pass Over 200 Square Feet
Tomatoes in a mixed bed: measure 2 teaspoons into the tank, fill to one gallon, and spray to a light, even glisten over the foliage.
Case B: 2-Gallon Pass Over A Larger Patch
Summer squash patch: measure 4 teaspoons, fill to two gallons, and walk the rows in a slow “S” pattern for full coverage.
Case C: Roses Along A Fence
Measure 1 tablespoon per gallon. Two gallons often cover a short fence line when you include the backs of leaves and stems.
When Things Go Sideways
- Spotty control: Coverage too light. Slow down, tighten the fan, and spray leaf undersides.
- Residue visible: Film heavy. Ease off volume or widen nozzle setting.
- Burned edges: Sprayed during peak heat or on wilted plants. Water earlier in the day and spray later in the afternoon.
- No improvement: Wrong diagnosis. Cross-check symptoms and widen your approach with sanitation and spacing.
Trusted References You Can Bookmark
For label-exact directions, see the EPA-approved label. The manufacturer also hosts a product page with usage guidance and crop lists; see the Ortho product page. Use both for the latest wording and any state-specific notes.
Final Prep Before You Spray
Walk the bed, prune the worst leaves, water early if soil is dry, and plan your route so you do not brush through wet foliage. With a dialed-in mix and steady coverage, you should see cleaner new growth and far fewer spots on the next pass.