Plant out sweet peas
It’s time to plant out your Sweet Peas if you are in the South, but hold off till the end of the month the further North you are. They grow best in rich soil with plenty of moisture and in cool conditions (not cold). The more you can enrich the soil with compost before planting, the bigger and healthier they will grow.
You can begin to sow lawn seed from late March, but there are more benefits if you can wait until September. The seedbed must be kept constantly moist till the grass is about 6cm. The adequate temperature of the soil for germination is 6-8 degrees Celsius, this is normally when the air temperature is above 10 degrees Celsius. Resist the urge to cut your grass down to summer heights. Set the blades high and trim the grass for the first few weeks, then reduce the height as the weather gets warmer and the grass grows more.
Harden Off Tender Plants
It is time to start bringing your tender plants outside, so that they can gradually acclimatise before being planted into a border or pot. Move them outside to a sunny but sheltered spot and allow them to get used to the changes in temperature and exposure to wind and rain. Use horticultural fleece to cover them if there is a cold night. Do this for two weeks before moving them to their final position if the risk of frost has passed.
Lilies provide one of the best and most fragrant summer displays, and you can now begin to plant them in pots. Plant the bulbs with around 4 inches of compost above the crown and keep them somewhere lightly shaded to grow. They will grow themselves if you provide good drainage and loose compost, such as a bark-based general-purpose compost. Move them to their final position when buds develop around May/June.