LIFTING POTATOES.

Star (Christchurch), Volume LXVI, Issue 20221, 3 February 1934, Page 29 (Supplement)

LIFTING POTATOES.

After what stage is it useless to leave potatoes in the ground longer, in the hope of their becoming bigger? There are, no doubt, many views on this subject, and one hears people say all sorts of strange things about the right time for digging, but, after all, the matter is extremely simple. So long as there is a green leaf on the original stem, so long will a certain amount of material be added to the tubers. The potato js a very provident vegetable, and almost as soon as it has rushed a leaf above ground it commences to store material for energies underground, but as long aA it is growing vigorously the amount carried below is relatively small. When the full growth has been reached, however, storage is accelerated, and the tubers increase in size. As the haulm gradually shrinks, proportionately more of the food material is withdrawn to the tuber. Once the leaves have turned completely yellow the tuber cannot increase in size, under any conditions, of weather, for the leaves are the only parts of the plant which can collect carbon from the air, and this carbon is the only thing from which the starch contents of the potato can be built up. Once potato haulm has died down in this manner, it is as well to take them up without delay, for the only change that can take place is the pushing forth of new growth from the tuber. Before fresh leave« can be formed the material of the tuber must be partly used up. However early they ripen, therefore, potatoes should be lifted as soon as they have died down, especially if it is early in the season, for a heavy fall of rain may cause growth to recommence. In the season like the present this is not only good policy, but may be turned to account, for if some of the early tubers nre laid out to become green tljey may be planted again, and should good rains fall will produce a second crop equal to the first.