The invention relates to a method of treating an outdoors area, wherein the outdoors area is sprayed with an aqueous solution to promote plant growth. To that end, the outdoors area is sprayed with a colloid solution, said colloid solution comprising - a discontinuous first phase comprising paraffin - having a carbon chain length between 18 and 40 carbon atoms； - a solidification point between 15 and 70°C； and - of which at least 6% by volume is linear； and - a continuous second phase comprising water； the colloid solution being applied in an amount of at least 0.1 g of paraffin per m 2 .
