It has continued to be a cold spring, this year. Warm days followed by clear nights mean that temperatures plummeted as any heat absorbed from the sunshine radiated from the ground overnight. Thank goodness we can get ahead in the greenhouse.
Most of my dahlias are overwintered under a heavy mulch in the garden but a couple of new varieties are in a tray of moist peat free multipurpose compost. Once they have started into growth, tubers will be ‘hardened off’ and transplanted into the border once the danger of frost has passed. Care must be taken when transplanting to avoid breaking off the new shoots; they should also be protected from slugs and snails, after planting.
Use peat free compost for all of your seeds. Larger seeds like peas, beans and sweetcorn can be sown in straight multipurpose compost having picked out larger lumps by hand. Instead of using pots, for larger seeds, you can also recycle drinking cups, with a hole punched in the base. Sow smaller seeds into finely sieved multipurpose compost or use seed compost.
Sow spinach, cabbage, calabrese, kohlrabi, cauliflower, lettuce, peas for pods and shoots, onions, salad onions, turnip, radish, beetroot, leeks, leaf beet and chard under glass in pots, trays or modules for ‘hardening off’ and transplanting later outdoors. Sow bunching or spring onions, round rooted beetroot and carrots and broad beans in pots for later transplanting in outdoors. There is no need to split the beetroot and carrots into individuals. Root crops like beetroot, radish, turnip should be transplanted outdoors once the root starts to form. Keep the glasshouse well-ventilated on hot days.
Mint grown in pots can also be forced for early harvest. Pot grown mint needs regular repotting, as it tends to become pot bound, the roots growing around the outside of the pot. Cut clumps vertically into halves or quarters depending on the size of the pot. Do this carefully using an old saw or bread knife. Saw off the bottom third and repot in fresh peat free multipurpose of soil-based compost like John Innes no 2. Encouraging pots of mint into growth in the greenhouse, allows you to see where living roots are placed before repotting and growing outdoors.
Tomato, Aubergine, Pepper and Chilli Plug plants will need potting on several times before moving to their final position in pots or the greenhouse border. Check root growth regularly, as the plants are growing very quickly and will soon become pot bound.
Sow melons, squash and cucumber seeds in modules or 7.5cm pots of multipurpose or John Innes no 1 potting compost ready for planting out in May once the danger of frost has passed. They can be germinated in a propagator at 15-18C (60-65F), keeping the compost moist with tepid water. It has long been recommended that they are sown on edge, but after many decades, this has recently been deemed un-necessary.
Citrus are hungry so need regular feeding. Use summer feed now until late October which is dissolved in rainwater, warmed in the greenhouse for at least 24 hours. Happy Gardening. Matt