Do as granddad and pee in the greenhouse
This leaf indicates a lack of magnesium.
Finnish horticulture scientists have figured it out, but the old garden owners have known it for more than a lifetime. It is regarding pee or maybe the more acceptable term urine
If your tomato has got yellow stains it might be a sign of a lack of magnesium. In this case, the Finnish scientists might help you.
What scientists have found out is that urine is a great fertilizer for tomatoes and cucumbers. The crops will simply grow bigger when they are irrigated with urine and you can’t even taste the urine in the tomatoes.
My granddad who passed away a long time ago learned the same and it was actually quite normal in the old days to empty the chamber pot in the kitchen garden. I remember my granddad peed in especially the strawberry bed, and he didn’t get why I was “allergic” to strawberries. The pee gave juicy and beautiful berries. He also had tomatoes growing up a wall of battens and plastic. They got some from the chamber pot too on a regular basis.
Ash and urine
According to the Finnish scientists, a mixture of urine and ash from the woodstove is the ideal mixture. The ash contains magnesium which is a requisite for the uptake of the nitrogen in urine. Not only tomatoes benefit from the mixture. Cucumbers got in the experiment bigger and the plants yielded better.
The mixture proportion is unknown but be careful with the ash and use only ash from pure wood, not from pressure impregnated wood.
Wood ash contains 7% potassium and 1,5% phosphor. Furthermore, it contains magnesium and plenty of lime and different heavy metals from the pollution of the city. That is why you should not exaggerate. Generally, you should only use 22 pounds of ash per 1076 square feet, so it’s not a lot of teaspoons you should use in the greenhouse. If you use ash in the kitchen garden, then strew it in a thin layer and only every second year. On the other hand, you don’t need to add lime.
Om Lars Lund
Danish horticulturist and journalist
Lars Lund has for many years engaged in the garden and greenhouse. Lars has published many books about greenhouses, and he has participated in many Danish horticultural TV shows. He is a walking garden encyclopaedia, and he has answers for most basic cultivation questions – also the more ambitious ones.