Working with clay soil – recognising clay soil
The best way to identify clay soil is to go and handle it. You can roll clay into a sausage between your hands, or squeeze it into a ribbon without it falling apart. It should feel quite smooth when rubbed between the fingertips and sticky when wet.
Disadvantages of clay soil
Clay soil can be very heavy and difficult to work with, especially when wet. Moreover, this soil often suffers from poor drainage so this is frequently the case.
Clay soil can also be compacted easily. So you should avoid walking on it whenever possible. Especially, just after rain as compaction occurs more readily when the soil is damp.
In spring, clay soil can take longer to warm up compared to other soil types like sandy soil. When it eventually does warm up, it can bake and become very hard during hot, dry periods.
Advantages of clay soil
Although good at retaining water, the structure of this soil also means it retains nutrients well, making it naturally quite fertile.
Since overworking clay soils often leads to compaction, they are often in their best condition when left alone. Clay will naturally aerate itself as it swells and shrinks as it becomes wet and dry. This is good news for those of us with a laissez-faire approach to gardening!
How to improve clay soil
There are a few steps one can take to improve clay soil for gardening. Raised beds provide a number of benefits: the soil can’t be compacted by being walked over; drainage is improved; and the soil warms up faster after winter.
How to break up clay soil
Alternatively, adding composted bark, sand or new topsoil will make clay far easier to work. The clay will also be less prone to compaction, and drainage will be improved. It’s worth noting that bark can draw nitrogen from the soil, so you may need to add additional fertilizer after taking this step.
Plants that like clay soil
Although clay soil is naturally fertile, the poor drainage qualities means that any plants which don’t like their feet wet, like those advertised as drought-tolerant, are best avoided.
Similarly, those plants requiring frequent work with soil like dividing or sowing should be left alone if possible.
According to the RHS, tree fruits and roses can grow very well in clay soil, as well as shrubs and other ‘woody’ plants.
Try planting Asters, Rudbeckia, Golden Rod, Yarrow, Sea Holly, Hostas, Yucca, Miscanthus, Mock Orange, Magnolia or Dogwood for bee-friendly plants that do well in clay soils.
Managing a lawn on clay soil?
Topdressing your lawn at least once a year will help to keep the soil in optimum condition for grass plants.