Some of my strawberry plants are very small and yellow and look rather sick, what is causing this?
Almost certainly, it is one of the many viruses that attack strawberries.
Sadly there is no control, and the affected plants should be removed and burned as soon as possible.
Keep an eye on the remaining plants, and remove any that show signs of going the same way.
Is it better to root strawberry runners in the soil or in pots sunk in the ground adjacent to the plants?
Ideally, sink small pots of compost into the ground close to the parent plants, peg a single runner into each pot.
When the runner is rooted, detach it from the parent plant and plant out into a well prepared site.
Only root healthy stock.
If you have had your plants for a number of years they may be affected by viruses, and might want replacing with new virus free stock.