If you’re growing coriander and it’s decided to bolt, then don’t worry…it’s actually worth allowing it to bolt and set seed as coriander seeds are a fab ingredient to have in the kitchen for making delicious curries.
Once the plant has bolted it’ll soon start to flower. The flowers will then form seed heads, the plant will turn brown and die and the seed heads will fall to the ground.
To store the seeds you need to intervene. Just as the plant begins to change colour and turn brown cut off the seed heads using scissors. Pop the seed heads into a brown paper bag and hang the bag until the foliage dries and the seeds naturally fall off. You can store the seeds in a sealed tupperware tub (or similar) and use them in your cooking. Or you could even try sowing them next spring.
Coriander seeds add loads of flavour to curries. Dry fry them quickly to release the aroma and then transfer to a pestle and mortar and grind them a little before adding them to curry pastes.