Patios frequently become coated with unsightly and hazardous 'green slime'—a mixture of moss, algae, and lichen—particularly following prolonged periods of cold, damp weather. This growth is not merely an eyesore; it creates a dangerously slippery surface that can lead to accidents. The primary culprits are persistent moisture, shade, and accumulated debris, which provide an ideal breeding ground for these spores to settle and flourish.
The Expert's Solution
Renowned horticulturist, author, and television presenter Alan Titchmarsh, 76, has shared a remarkably effective method to combat this issue, one he employs in his own garden. In a recent episode of his YouTube series, 'Gardening with Alan Titchmarsh,' he focused on maximising space in compact areas, which included revitalising his terrace.
Why Pressure Washing Works
"Stone terraces are lovely, but they do get green slime on them, which makes them really quite dangerous," Titchmarsh explained. He strongly advocates for the use of a pressure washer over alternative cleaning techniques, especially for mostly flat garden surfaces. This approach not only enhances safety but can dramatically improve the patio's appearance. "Sometimes it can look like a new patio even by giving it a good clean," he noted, adding that the slabs will appear "quite pristine" post-cleaning.
Mastering the Technique
Titchmarsh demonstrated his precise pressure washing method in the video. "I've got my pressure washer here with the correct nozzle attached, and I'm going to work my way right across the patio," he said. He emphasised a critical detail: the distance between the nozzle and the paving surface. "The closer you get, the more that will come off, the cleaner it will be."
However, he issued a crucial warning to avoid damaging the patio's structure: "Try to avoid putting the pressure washer directly onto the pointing between because it will pull that out as well." He also advised against using this forceful method on delicate garden ornaments, stating, "They're lovely with a bit of patina on them."
Stunning Before-and-After Results
The transformation showcased in Titchmarsh's video was striking. The 'before' footage revealed a terrace heavily stained with lichen and extensive green areas of moss and algae. After a thorough pressure wash, the patio looked brand new, completely free of any green staining, effectively restoring it to a safe, like-new condition.
Beyond Cleaning: Creating a Garden Room
While the primary focus was on cleaning, Titchmarsh's project extended to creating an "outdoor open garden room" on his south-facing terrace, which he described as a "sun trap." In addition to the pressure washing demonstration, he detailed how to prepare and arrange softwood planters to act as the 'walls' of this space. He also shared tips on selecting plants for window planters and the proper watering techniques for newly planted specimens.
This comprehensive guide from a trusted gardening authority provides a clear, actionable solution for homeowners battling with slippery, algae-ridden patios, promising not only improved safety but a significant aesthetic upgrade.
