This is a regular task, as these materials soon decay in well-aerated soils. Install a hose sprinkler system for important areas, such as summer flower beds. Mulch plants regularly. Apply a general fertilizer to flowers each spring. When planting, add compost or peat to the soil, and also a sprinkling of bone meal.
Alkaline soils contain a high proportion of chalk.
Alkalinity is at the opposite end of the scale from acidity, and in the garden these can be measured on a pH scale, from 0 to 14. A reading of 7.0 is chemically neutral, but most plants happily grow in 6.5, which is slightly acid. The scale is logarithmic, and therefore potentially misleading. A difference of 1.0 on the scale represents a soil ten times more acid or alkaline. Simple but effective pH soil-testing kits are available from gardening shops and nurseries.