In article , Coffea ramosa
writes

Might be a stupid question, but what is the runners of a strawberry plant?

When a strawberry plant flowers, those flowers will (hopefully) become
pollinated, then they will turn into first green, then red fruit - i.e.
strawberries. In the flesh of the fruit are tiny dark specks which are
seeds of the plant, which could be used to propagate further plants.
But strawberries have a secondary method of propagation - by runners.

At about the same time as the flowers are turning into fruit, small
stems with tiny leaves on them can be seen growing out from the base of
the plant. Those stems will quickly grow quite long (i.e. they will
'run') and their small leaves will develop roots. If left to do so, the
node with the leaves on will settle on the ground and the roots will
grow into the soil. Then the runner will continue to grow on to produce
further new plantlets. One plant can produce dozens of runners.

At this point, it is usual to take off the runners so as to divert the
energy of the plant into fruit production. But strawberry plants need to
be replaced regularly, so some of the runners can be kept for that
purpose. We don't let strawberry runners grow in the soil around the
plant, we strike them into pots and let them grow until the stem of the
runner darkens and divides. That will be in about July-September. By
then the potted new plants will be ready to be put into their new
growing positions - or they can be kept in the pots and grown on inside
for early fruit production.
--
Alan & Joan Gould - North Lincs.