April 8th-14th
An Alpine gravel garden must have its soil thoroughly prepared before planting. A well-drained, airy composition is what you're after. Dig in lots of organic matter (garden compost or a proprietary soil conditioner), and if the soil is heavy, add plenty of grit. Let it settle for a week or so before planting. If you like, you can cover the surface with a special weed-excluding mesh fabric and plant through slits in it. A word of caution though: gravel sometimes works its way off these fabrics, revealing the ugly black material - so keep an eye out for slippage. Water the new plants well. Add at least a 5 centimetre layer of gravel, taking care around vulnerable plants.
After that, maintenance is minimal and consists of deadheading faded flowers, and giving an annual spring feed (Ciaran Burke uses pelleted chicken manure). The gravel (and the fibre mesh, if you use it) helps to conserve moisture, so you should not need to water, except in periods of prolonged drought.