The Care of Strawberries
Weeds must be kept down in the strawberry bed but any hoeing must be very shallow to avoid root damage: it is better to use paraquat / diquat weedkiller as much as possible, being very careful not to let it touch the leaves of the strawberry plants.
When the berries begin to swell take steps to prevent soil-splashes spoiling them. There are three ways, the traditional one being to spread a little clean straw over the soil and beneath the fruit trusses. Alternatively buy proprietary strawberry mats and lay one of these round each plant, or put down black polythene tucking it into the soil or weighting it down with stones to prevent the wind getting beneath it. Never put straw or other mulches down too early as they may increase the risk of frost damage to open flowers.
Quite early in the season summer-fruiting strawberries start .trying to propagate their kind by producing runners-cord-like growths on which tiny plants develop. These should always be cut off as soon as seen unless vou wish to raise new plants. Unless you are cry sure that your strawberries are quite free from virus disease infection (to which t hey are extremely prone) it is wiser to leave this job to the experts and buy new plants as required. It is never advisable to keep a strawberry bed for more than three seasons.
If you decide to raise your own plants, simply sink a 3-in. Pot of good growing compost (John Innes potting compost or soilless compost) into the ground by the parent plant where the plantlet on the runner can be bent down. Hold the runner in place with a stone or `hairpin’ of galvanized wire and pinch out the tip of the runner to prevent further growth. At the end of July the new plant can be separated from its parent and a week or two later lifted and replanted.
As soon as picking is finished, cut all the old leaves off with shears and deal with any weeds. In early autumn rake in oz. per sq. yd. Each of sulphate of ammonia and sulphate of potash and put down a mulch of well-rotted farm or stable manure or garden compost (about 5 lb. Per sq. yd.). Greenhouse Culture
The strawberry season can begin very much sooner if you Iorce a few pots in the greenhouse. ‘Royal Sovereign and ‘Grandee’ are good varieties lot this. Early-rooted runners are needed for this purpose-late July if possible. Plant in 9-in. Pots using JIP 3 potting compost. Stand the pots in the open on a sheet of polythene until mid-November and then either turn them on their sides (to prevent over-watering) or put them in a cold frame. Towards the end of January transfer to the unheated greenhouse. When fresh growth becomes visible, start watering cautiously and turn on the artificial heat. A night temperature of 45°F (7U) will be quite sufficient at first. Let this rise gradually to 5oT (I&C) when the blossom trusses are seen. Pollinate the flowers by hand, dusting their centres with a camel’s-hair brush. When the blossom has fallen the night temperature may be permitted to rise another five degrees (F) to t3°C and gentle liquid feeding should begin and be continued until the berries colour.
Cloches and Tunnels
The strawberry season can also be advanced two or three weeks by covering first-year plants with cloches or polythene tunnels at the end of February. Deal with all weeds before covering. Keep closed until the blossom opens and then open cloches or pull them apart slightly and open tunnels fully by day to allow entry of pollinating insects. Close tunnels and cloches again by 4 p.m. In April and May ventilate in sunny weather to prevent a dangerously high build-up of temperature. In dry weather watering may be necessary. Do this in the morning to let the plants dry before ventilation is closed again.
These need slightly different treatment. In the first season, nip off all flower trusses which appear before June. In subsequent years all blossom may be allowed to develop. Some do not produce runners freely; where new plantlets appear they may be allowed to root and may flower and fruit the same season. After fruiting the first year cut off all old leaves but in subsequent years leave them to fall naturally. Always burn strawberry leaves after removal.