We finished a house in Hamburg in the last week of March. Two coats, Hardie board, a colour the homeowner had gone back and forth on for the better part of a month.
Nine days later she called. The whole west elevation had gone yellow-green overnight, worse near the gutters, worse again in the corners where the wall stays shaded until noon.
She had not said the word warranty yet, but it was clearly sitting on the desk in front of her.
Here is the answer we gave her, and it is the same one we will give you. Pollen sitting on a wall is a cleaning question, not a coating failure. Nothing has gone wrong with the finish.
What matters now is timing. The wrong response in the first two weeks can do real damage, and the right response costs almost nothing.
The short answer: what should you do about pollen on freshly cleaned or freshly coated siding?
Pollen on a fresh finish is a cleaning problem, not a coating failure. Keep the pressure washer away until the finish is fully cured, which is commonly two to four weeks. Rinse gently with a garden hose from the top down, in the morning, before the sun warms the wall. Then wait for the tree count to drop and have the house washed properly in late May.
Rinse gently with a garden hose, top down, in morning light.
Wait out the cure period before any pressure or chemistry touches the wall.
Wait for the tree pollen peak to pass before paying for a full wash.
Book that wash for late May, and book it in March or April to get the slot.
Why does pollen stick harder to clean siding than to dirty siding?
Because it does, and the mechanism is worth understanding before you decide what to do about it.
Morning dew and Ohio Valley humidity
Pollen does not simply land and sit. It lands on a damp surface.
Ohio Valley humidity means most exterior walls carry dew from late evening through mid-morning. Pollen settles into that moisture film, and as the sun warms the wall and the water evaporates, the pollen is pressed against the surface and left bonded to it.
Once that has happened, a garden hose will lift the loose top layer and leave the bonded layer behind. That is why a rinse looks like it half worked.
Why smooth, light siding shows it worst
The newer Hardie board and stucco builds around Beaumont and Hamburg show pollen harder than anything else in Lexington, for two plain reasons.
The surfaces are smooth and light coloured, so a yellow-green film has maximum contrast against them. And these are usually unshaded lots with no mature canopy to break the drift.
North and west elevations hold it longest, because they dry slowest. Horse farm properties toward Versailles and Georgetown get the worst of it, with open land exposure and nothing between the trees and the wall.
Why a new finish appears to attract more pollen
Here is the uncomfortable part, said plainly rather than talked around.
A fresh finish does hold pollen more readily than a weathered one, for the first season. Part of that is surface energy on a new film. Most of it is visibility, because a clean uniform wall shows every particle the way a freshly washed dark car shows dust.
No coating repels pollen. Not ours, not anybody’s, and anyone telling you otherwise is selling something. What a good finish does is release it easily when it is finally washed.
When is pollen season in Lexington and Central Kentucky?
Planning beats reacting, so here is the calendar.
Tree pollen
Kentucky’s pollen season commonly starts in February, later than warmer states because of the colder winter, and tree pollen peaks through April and May.
Oak, birch, cedar, maple, juniper, pine and poplar carry most of the local load, with oak the dominant allergen around Lexington. Oak is also the heaviest visual offender, which is why the yellow-green film peaks at the same time the allergy reports do.
This is the season that coats walls. It is also the season most people book exterior work in, which is exactly how a nine-day-old finish ends up looking like the one in Hamburg.
Grass pollen
Grass takes over through late spring into early summer, including Kentucky bluegrass and Timothy.
This is why a wall washed in early May often looks dusty again by mid-June. The tree count dropped, but the grass count picked up, and the wall does not distinguish between them.
Ragweed and the close of the season
Ragweed runs from August through October, and the overall season closes out in late October or early November.
The months worth watching are April, May, June and September. Everything else is comparatively quiet.
A twelve month Lexington washing calendar
| Months | What is airborne | Wash or wait |
| December to January | Very little | Fine to wash, though cold limits chemistry |
| February to March | Tree season beginning | Wash only if needed, expect it to reload |
| April to May | Tree peak, heaviest of the year | Wait. Rinse only |
| Late May to June | Tree count dropping, grass rising | The main annual wash window |
| July to August | Grass falling, ragweed starting | Good secondary window |
| September | Ragweed peak | Wait. Rinse only |
| October to November | Season closing | Good window for a second wash if needed |
Does pollen actually damage a coating, or does it just look bad?
Three real pathways, and none of them is pollen eating your finish.
What pollen does not do
It does not dissolve a cured coating. It does not etch a sound film. And it does not permanently stain intact siding, whatever a neighbour tells you.
If your finish is sound, what you are looking at is a layer sitting on top of it.
What pollen does do
A bonded pollen layer holds moisture against the wall. That is the actual damage pathway, and it is indirect.
Siding under a bonded layer stays wet longer than it should. North facing elevations, which already dry slowest, can stay damp for weeks through a wet Kentucky spring. Damp surfaces degrade faster, and more importantly they seed algae and mildew.
The green streaking people find in July is very often the pollen layer from April, still there, now growing something.
The acidity question
Pollen becomes mildly acidic once water activates it. That is true and it gets quoted a lot.
Keep it in proportion. Mild acidity matters over repeated seasons on a surface nobody ever cleans. It does not matter much over one April on a wall that gets washed in late May. The mechanism is real, the timescale is long.
How to tell pollen from a real finish problem
This is the diagnostic most people want and nobody publishes.
Pollen rinses lighter with plain water, even if it does not come off entirely. It sits in even drift patterns across an elevation. It concentrates near gutters, corners and any place water runs or collects. It is on the surface, and it feels like a film rather than like the wall.
Blistering, chalking and adhesion failure do none of that. Blisters are raised. Chalk comes off on your hand as a powder from the finish itself, not as yellow dust. Adhesion failure shows as lifting edges and flaking, usually starting at transitions and trim.
If a plain water rinse visibly lightens it, you are looking at pollen.
How soon after a new coating can you wash the house?
The question nobody else answers, and the one that decides whether this ends well.
Dry versus cured
These are three different things and they happen days apart.
A finish is dry to the touch in hours. It is broadly rain safe at 24 to 48 hours. It is fully cured at roughly two to four weeks, depending on temperature and humidity.
Ohio Valley humidity pushes that toward the long end. A wall coated in a damp Kentucky April is curing more slowly than the same wall would in a dry September.
The 30 day rule of thumb
Do not pressure wash a new finish for at least 30 days.
That is the working rule, and it is deliberately conservative because most people cannot tell by looking whether a film has finished curing. If your installer or the product’s care guidance gives a specific figure, that figure overrides this one. Ask for it in writing.
Our own coating is applied as two airless sprayed coats at roughly 80 percent solid content with ceramic microspheres, 8 to 10 times thicker than paint. A thicker film is a good thing in service and a slower thing during cure, so err long rather than short.
What is safe before full cure
Plenty, actually.
A light garden hose rinse, no nozzle pressure, from the top down
A soft microfiber cloth with plain water on reachable areas
Mild soap and water, rinsed thoroughly, on doors and trim
A leaf blower on low for dry pollen on porches, sills and railings
None of those apply pressure or chemistry to the film. All of them will noticeably improve how the house looks while you wait.
What is allowed at each stage
| Stage | What has happened to the film | What is safe |
| Day 0 to 1 | Surface skinned, soft underneath | Nothing. Do not touch it |
| Day 2 to 7 | Rain resistant, still curing | Gentle hose rinse, top down, morning only |
| Day 8 to 14 | Curing continues, hardness building | Hose rinse, soft cloth, mild soap on trim |
| Day 15 to 30 | Approaching full cure | As above. Still no pressure, still no chemistry |
| Day 30 plus | Cured under normal conditions | Full soft wash, ideally professional on a warranted finish |
If you are inside that window and unsure what you are looking at, we will come out and tell you. Free, and there is nothing to buy at the end of it. Call (859) 695-2718.
How do you clean pollen off without voiding the warranty?
Real numbers, so you can judge whoever ends up holding the wand.
Pressure
Soft washing runs 60 to 100 PSI at the nozzle. Under 500 PSI is the safe ceiling for siding.
A consumer pressure washer from a hardware store commonly runs several times that. That is how water gets driven behind siding panels, into weep holes, and under trim, where it sits and causes the exact moisture problem you were trying to prevent.
Pressure is not what removes pollen. Chemistry and dwell time are. Pressure is only what damages things.
Chemistry
A standard house wash lands around 1 to 1.5 percent sodium hypochlorite measured at the wall. Heavy shaded growth runs 2 to 3 percent. Roof mixes run 3 to 6 percent and have no business on siding.
On painted or coated surfaces this needs care. Sodium hypochlorite can lift and streak a finish, so it requires a pre-wet, a cut mix and a spot test in an inconspicuous area first. It is not a standard wash and it should not be treated as one.
That is the honest reason we steer coating customers toward having it done rather than doing it themselves. Not because a homeowner is incapable, but because the margin for error on a warranted finish is small and the downside is a streaked elevation.
Method
Dwell 5 to 10 minutes, and never let the mix dry on the surface. A dried mix is what causes streaking, far more often than the concentration does.
Add surfactant at roughly 1 to 2 tablespoons per gallon so the solution clings instead of running straight off.
Rinse top to bottom. Clear the weep holes at the base of siding panels, since that is where pollen and residue collect. Finish with a low pressure pass across the base of every elevation.
Work in the morning or on an overcast day. A hot wall in direct sun dries the mix before it can be rinsed.
Protecting everything else
Pre-wet beds, shrubs and sod before you spray anything, and rinse them again afterwards. Sodium hypochlorite is hard on plants that are dry when it lands.
Keep pets inside until everything has dried. And never mix sodium hypochlorite with ammonia or with any cleaner containing it.
What actually puts a coating warranty at risk
Each of these is a mechanism, not a scare story.
Abrasive pads and wire brushes. They scratch the film, and scratches hold moisture and dirt permanently.
Solvent cleaners. They soften or dissolve the binder that holds the coating together.
High pressure held close to the wall. It drives water behind panels and can cut into the film at edges and transitions.
Washing before cure. The film is still forming, and mechanical or chemical interference during that window leaves permanent marks.
Read your own warranty document for the specific cleaning and maintenance language on your finish, and ask your installer what is permitted before you or anyone else touches the wall.
Should you wash now or wait until pollen season ends?
Most people should wait, and rinse in the meantime.
Why washing in mid April is usually wasted money
The tree count refills the wall within days.
You can pay for a professional wash on the second Saturday in April and have a visibly yellow west elevation again by the following weekend. Nothing was done wrong. The season simply has not finished producing.
The late May window
Once the tree peak passes, a wash holds. Late May into early June is the main annual window in Central Kentucky, and it is the one to aim for.
Book it in March or April. Everybody in Fayette County wants the same three weekends, and the calendar closes early.
The exceptions worth washing early for
Four situations justify washing in the middle of the season.
A listing or an appraisal with a fixed date. An event at the house. Visible biological growth rather than dust, meaning green or black streaking rather than yellow film. And pollen packed into weep holes, gutter lines or window channels, where it holds water rather than just sitting on the surface.
Outside those, rinse and wait.
What this looked like on one Lexington house
Nine days after a two-coat Hardie board job
The west elevation had gone yellow-green across its whole face. Heaviest along the gutter line, and heaviest again in the two corners that stay shaded until midday.
What she was looking at was oak and maple, which is what most of Lexington is looking at in the second week of April.
What we told her not to do, and the one thing she could do
We told her not to touch it with a pressure washer, and specifically not to let anyone else touch it either. The coating was nine days into a cure that runs two to four weeks, and a wand on that wall would have left marks that no amount of later washing would remove.
What she could do that week was rinse with a garden hose from the top down, in the morning, before the sun warmed the wall. She did that twice. It took about twenty minutes each time and it made a visible difference.
The late May wash
We came back at the end of May, once the tree count had dropped, and did the wash properly at low pressure.
Same wall, same colour, no marks, no streaking. The finish had never been damaged at any point.
For context on us rather than on the wall, we hold 4.9 stars from 51 reviews across the company, and 4.2 stars from 9 local reviews on our Lexington profile. We would rather you see both.
What not to do when pollen covers a fresh finish
Every item here is something we have been called out to look at afterwards.
Renting a pressure washer and going in at full trigger
From six inches away, on a wall that is two weeks old. This is the one that causes permanent damage, and it is the most common.
The marks it leaves are not pollen and they do not wash off.
Scrubbing with a deck brush or an abrasive pad
On an uncured film, a stiff brush burnishes the surface and changes the sheen in patches. The pollen comes off and you are left with a wall that has visible scrub marks in raking light.
Hiring the first truck that knocks during pollen season
Pollen season brings door knockers the same way storm season does.
If somebody offers to wash your house, ask three questions before agreeing: what pressure do you run at the nozzle, what mix do you use on a coated surface, and how old is the finish. A professional answers all three immediately. Anyone who cannot should not be pointing a wand at your house.
Washing at midday on a hot wall
The mix dries before it can be rinsed, which is the single most common cause of streaking on a house wash.
Morning or overcast, always.
Frequently asked questions
Does pollen permanently stain siding? No, not on a sound, intact finish. Pollen sits on the surface and comes off with a proper low pressure wash. What does cause lasting marks is the algae and mildew that grow in a bonded pollen layer left in place for months, and the scrubbing or high pressure people use trying to remove it themselves.
How soon after a new coating can I pressure wash the house? At least 30 days as a working rule, and only after the finish is fully cured. Cure commonly takes two to four weeks depending on temperature and humidity, with Kentucky spring humidity pushing toward the longer end. Your installer’s stated cure time overrides any general rule, so ask for it in writing.
Will washing my house void the coating warranty? Not washing it correctly. What creates problems is high pressure held close to the wall, abrasive pads or wire brushes, solvent cleaners, and washing before the film has cured. Read the cleaning and maintenance language in your own warranty document, and ask your installer what is permitted before anyone touches the surface.
What PSI is safe for washing siding? Soft washing runs 60 to 100 PSI at the nozzle, with under 500 PSI as the safe ceiling for siding. Consumer pressure washers routinely run several times that, which drives water behind panels and into weep holes. Removal comes from chemistry and dwell time, not from pressure, so higher pressure buys damage rather than cleanliness.
When does pollen season end in Lexington, KY? Tree pollen peaks in April and May and drops off through late May. Grass carries into early summer, ragweed runs August through October, and the overall season closes in late October or early November. The best annual washing window in Central Kentucky is late May into early June, once the tree peak has passed.
Will a garden hose get pollen off? Partly. A hose lifts the loose top layer and will visibly lighten a wall, which is worth doing while you wait out a cure period. It will not remove the bonded layer that morning dew pressed into the surface. That needs a proper low pressure wash with detergent and dwell time.
Does pollen damage paint? Not directly. Pollen does not dissolve or etch a sound film. The damage is indirect: a bonded layer holds moisture against the wall, slow drying elevations stay damp for weeks, and damp surfaces seed algae and mildew. Pollen also becomes mildly acidic once wet, which matters over years of neglect rather than one spring.
How often should I wash my house exterior in Kentucky? Once a year suits most Lexington homes, timed for late May or early June after the tree peak. Shaded north elevations, heavily wooded lots and houses under mature oaks often benefit from a second wash in autumn once ragweed has finished. Rinsing in between costs nothing and helps considerably.
Is soft washing better than pressure washing for siding? Yes, for siding. Soft washing uses low pressure with detergent and dwell time to break the bond, which is what actually removes pollen, algae and mildew. High pressure removes some of it while forcing water behind panels and risking damage to the film, trim and sealant. Pressure is appropriate for hard flat surfaces, not walls.
My new coating looks discoloured, is that pollen or a defect? Almost always pollen, and there is a quick test. Pollen lightens noticeably with a plain water rinse, sits in even drift patterns, and concentrates near gutters and corners. A finish problem shows as blisters, powdery chalk from the film itself, or lifting and flaking at edges. If a rinse changes it, it is on the surface.
Not sure if it is pollen or something else? Have someone look at it
The homeowner in Hamburg spent nine days thinking she had wasted her money. She had not. The pollen was never the problem, and the only thing that could have caused real damage was the response she was considering.
If you are looking at a wall right now and cannot tell whether it is pollen or something worse, that is a reasonable thing not to be sure about from the ground.
We will come out and look at it, tell you which one it is, and tell you when it is safe to wash. Free, on site, with nothing to buy at the end.
Rhino Shield of Cincinnati and Kentucky, 222 Midland Ave #6109, Lexington, KY 40508. Call (859) 695-2718, Monday to Saturday, 9:00 AM to 7:00 PM. We cover Lexington and Fayette County along with Nicholasville, Georgetown, Versailles and Richmond.
