{"id":1004,"date":"2026-08-10T09:12:00","date_gmt":"2026-08-10T09:12:00","guid":{"rendered":"https:\/\/pressure.mobi\/blog\/?p=1004"},"modified":"2026-08-10T09:12:00","modified_gmt":"2026-08-10T09:12:00","slug":"algae-on-vinyl-siding","status":"publish","type":"post","link":"https:\/\/pressure.mobi\/blog\/algae-on-vinyl-siding\/","title":{"rendered":"Why algae always starts on the north wall"},"content":{"rendered":"<p>The green film on your siding is algae, it always colonises the north side first, and the reason is sunlight \u2014 or the lack of it. Understanding why it grows where it grows tells you a lot about how <a href=\"\/house-washing\/\">house washing<\/a> keeps it away.<\/p>\n<h2>Shade, moisture and why north matters<\/h2>\n<p>Algae needs moisture to establish. A wall that dries quickly after rain or dew is hostile territory; a wall that stays damp for hours is a habitat. North-facing walls in this hemisphere get the least direct sun, dry slowest, and so green up first \u2014 followed by any wall shaded by trees, and the strips behind shrubs where air movement is poor.<\/p>\n<p>This is why two identical houses on the same street can look completely different. It is not the siding, and it is not the owner. It is the orientation and the tree cover.<\/p>\n<h2>Why it comes back faster after a bad wash<\/h2>\n<p>Pressure washing algae removes the visible growth and leaves the root structure in the siding&#8217;s texture. The colony regrows from that base within a season, which convinces homeowners that washing is pointless.<\/p>\n<p>A soft wash kills the organism outright. Regrowth then has to start from new airborne spores rather than an established base, which is the difference between months and years.<\/p>\n<h2>Slowing it down between washes<\/h2>\n<p>Trim vegetation back from the walls so air can move and the surface can dry. Redirect sprinklers that hit siding \u2014 irrigation water on a shaded wall is an algae subsidy. And accept the geometry: a north wall under oaks will always need attention more often than a south wall in full sun.<\/p>\n<p>Annual washing keeps most homes ahead of the growth. Heavy shade sometimes justifies twice a year, and that is a property fact rather than a failure.<\/p>\n<p><em>If the north wall has gone green, the rest is coming. A photo gets you a quote the same day.<\/em> <a href=\"\/house-washing\/\">Read more about house washing &rarr;<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The green film on your siding is algae, it always colonises the north side first, and the reason is sunlight \u2014 or the lack of it. Understanding why it grows where it grows tells you a lot about how house washing keeps it away.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"pagelayer_contact_templates":[],"_pagelayer_content":"","footnotes":""},"categories":[12],"tags":[],"class_list":["post-1004","post","type-post","status-publish","format-standard","hentry","category-house-washing"],"_links":{"self":[{"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/posts\/1004","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/comments?post=1004"}],"version-history":[{"count":1,"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/posts\/1004\/revisions"}],"predecessor-version":[{"id":1107,"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/posts\/1004\/revisions\/1107"}],"wp:attachment":[{"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/media?parent=1004"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/categories?post=1004"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/pressure.mobi\/blog\/wp-json\/wp\/v2\/tags?post=1004"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}