The ITV star, who returns to TV screens with Love Your Weekend, is considered a trusted voice in the world of gardening.
But some may raise an eyebrow at one of his latest tricks, which he claimed was used by “old gardeners”.
As spring draws nearer, hopeful growers are looking to plant seeds outside and inside.
For those who are looking to sow seeds outdoors, one of the biggest obstacles can be knowing if it is warm enough for plants to survive.
But Titchmarsh claimed to have stumbled across an unlikely tip for testing the soil, which he shared in a recent YouTube video for Waitrose and Partners.
He said: “The old gardeners used to do several tricks.”
The first he listed was analysing the surroundings to detect any other signs of life.
Titchmarsh said: “First of all, when weed seeds were beginning to germinate in spring.
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Titchmarsh referred to the hack parents use for testing if bathwater is too warm or too cold for their child by sticking their elbow into the water.
Titchmarsh claimed you could take a similar approach in the gardening world.
He said: “Just see if [the soil] feels warm to your elbow.”
Titchmarsh’s last tip was a little less common and was said to have been done “quite a few years ago”.
The star didn’t cite the exact time period it came from nor the individuals who tried this third test.
Titchmarsh said: “In extreme cases and quite a few years ago.
“And I never used it.
“Is to drop your trousers and sit with your naked bottom on the soil.
“If you go ‘Oh that’s cold!’, it is too cold for seeds.”
Titchmarsh reiterated it wasn’t a gardening hack that he was keen to try out.
He said: “I think perhaps the elbow is preferable.”
The website Gardening etc claimed that Titchmarsh’s tips could be used for vegetable patches or flower beds “alike”.
Writer Teresa Conway explained: “Because any type of seed could be damaged and fail to germinate if they are planted too early in soil that is too cold.”
Gardening expert Thompson Morgan revealed that half-hardy plants could be sewn in March.
They include bare-root roses, daffodils, hyacinths and lilies.
Mr Morgan explained that there were a number of vegetables and fruits that could be germinated indoors or in a greenhouse too.
He listed sweet peppers, cucumbers, chili seeds, certain tomatoes, celery and more.
Love Your Weekend With Alan Titchmarsh airs at 10am Sunday on ITV.