What to do...
* Continue to sow small quantities of radish and lettuce at two-weekly intervals. Theoretically this should give you a continuous supply through the season. In practice, crops tend to race or sulk so that you end up, as always, with too much or too little. Try 'Red Salad Bowl' lettuce for its frilly cut-and-come-again leaves or a completely different Cos type of lettuce for sweet, bright green leaves.
* Sow runner beans, either inside in pots or boxes where you can hurry them on, or directly outside. Either way you ought to have a couple of loads of compost seething quietly at the bottom of the trench they are to go in.
* In the south, make sure that plants such as tomatoes and marrows are properly hardened off, before planting out. This also applies to tomato plants that you have bought, rather than raised yourself. They have often been whipped directly from polytunnel to sales point, with no hardening off in between. In the north, it is safer to wait until the beginning of June before risking tomatoes outside.
* Plant dahlias, covering the tubers with about three inches of soil. The bronze-leaved varieties are showy, but all dahlias are difficult to work into the average flower border. They leave large holes until midsummer and then overcompensate by crowding out their neighbours. Use them to follow on from oriental poppies, which won't be bullied.
* Prune osmanthus to shape after it has flowered. They make very attractive domes if you cut back over-ambitious leaders at this time of year. Aim for a well-balanced, roughly rounded shape.
What to see...
* At the Mauritshuis Museum in The Hague there's an enchanting exhibition of the 17th-century paintings of Adriaen Coorte. Asparagus, redcurrants, strawberries, each painting is a tiny still-life, simply composed, but ravishing. The exhibition continues until 8 June and is open Mon-Sat (10am-5pm) and Sun (11am-5pm). Admission €9.50 (£7.50). There's a sumptuous catalogue by Quentin Buvelot (€22.95); visit mauritshuis.nlReuse content