ATAK Optic Foliar Concentrate - Late-Bloom Powdery Mildew Spray Treatment
Best for: Growers who've spotted powdery mildew late in flower and need a treatment that's safe to use close to harvest.
Our thoughts
Mildew showing up in week 6 of flower is every grower's nightmare, because most treatments either aren't safe that close to harvest or leave residue on the finished flower. ATAK is built specifically for that problem. It's a targeted tool for an emergency, not a general-purpose foliar feed, so use it for what it's actually designed to do.
ATAK is a concentrated foliar spray from Optic Foliar formulated around copper sulphate and organic ingredients, designed specifically to knock back powdery mildew on the leaf surface. Unlike a lot of mildew treatments that carry harvest-interval warnings, ATAK is designed to be used late into flower, including close to harvest, without leaving lasting chemical residue on the finished plant when used as directed.
It's typically applied alongside Optic Foliar's Transport+ surfactant, which helps the spray spread and penetrate the leaf surface rather than beading up and rolling off. It's a spot-treatment tool aimed at an active mildew outbreak rather than a preventative feed you'd spray on a routine schedule.
How it compares
ATAK sits in the late-flower mildew treatment category, a smaller niche than general foliar feeds.
- Vs Sierra Natural Science SNS-244: both are marketed as safe to use close to harvest; SNS-244 leans on a botanical fungicide formula, ATAK on a copper sulphate base.
- Vs Zerotol HC: Zerotol is a broader-spectrum disinfectant/fungicide used earlier in a grow cycle, whereas ATAK is specifically positioned for late-bloom spot treatment.
- Vs general preventative sprays used earlier in veg or early flower: those aren't designed for late-flower use, which is exactly the gap ATAK is built to fill.
If you need something for an active mildew problem in late flower, this is a purpose-built option rather than a repurposed general fungicide.
Usage guidance
ATAK is a concentrate, so dilution ratios matter.
Mixing
Use at 10ml of ATAK concentrate per litre of water, combined with 7.5ml of Transport+ per litre, to help the spray spread and adhere to the leaf surface.
Application
Spray the tops of the leaves and affected areas as a spot treatment rather than a full-canopy soak, focusing on visible mildew.
Timing
ATAK is formulated for use in late flower, including close to harvest, but always check your own local guidance and the current product label for the exact pre-harvest interval before spraying.
Lights-on use
The formula is designed to be applied with lights on without leaf burn, useful when you can't wait for lights-off to treat an active outbreak.
Technical specifications
- Active basis: Copper sulphate and organic ingredients
- Format: Concentrate, dilute before use
- Mixing ratio: 10ml ATAK + 7.5ml Transport+ per litre of water
- Sizes available: 250ml, 500ml, 1 litre
- Coverage: 250ml makes approx. 25L of spray solution
- Application method: Foliar spray, spot treatment
- Brand: Optic Foliar
Who this is for
- Growers dealing with an active powdery mildew outbreak in mid-to-late flower
- Anyone who needs a treatment option that doesn't force them to write off a near-finished crop
- Growers already using Optic Foliar's Transport+ or other foliar products who want a matched mildew treatment
Not intended as a routine preventative spray - keep it on hand for when mildew actually shows up.
Our take
This is a specialist tool for a specific, stressful problem - mildew showing up when your crop is nearly done. It does one job, and it's designed to do it without wrecking your harvest window.
One worth keeping on the shelf as insurance even if you don't need it every grow - does exactly what it should when the problem actually turns up.
