August – the month when many tomato crop are at their best. A warm, sweet, succulent, sun ripened tomato, picked and eaten straight from the plant is one of the epicurean summer delights of gardening. The acid, mainly citric, content of the fruit is due to the potash the plant has access to hence the saying ‘ more potash more acid’. The sugars, mainly fructose, depend on the sunshine the plant receives, hence ‘more sun more sugar. We have no control over the sunshine but we can make the best use of what we get by letting it reach the fruit.
If yours are slow to ripen remove the leaves up to the first truss and from now on deleaf each truss as it starts to ripen. With a sharp knife cleanly cut through the collar – the point where the leaf petiole joins the stem. If this is done early in the day the wound has time to callus over before nightfall, this helps to keep disease at bay. When leaves are snapped off the torn wound is open to any botrytis spores that are often floating around.
It is warmth that starts the ripening process and while the optimum temperature is 68F / 20C, most varieties will ripen in the temperature range of 65 -75 F / 18- 25C.
Mature pale green tomatoes usually ripen to an orangey red as they contain more carotene than lycopene in their makeup. Mature dark green tomatoes have more lycopene than carotene and usually ripen to a dark red. Really big beefsteak tomatoes can take up to a month longer than their normal sized cousins but given plenty of sunshine are worth waiting for.