I have found that the plants only produce good yields for a couple of years, so every 3 yrs I replace with runners, and don't forget to rotate the patch every 3 yrs if possible.
.....also, in the first year. Don't allow the plants to develop fruit, nip the flowers off and feed with a balanced food fertilizer. By doing this, your encouraging the plant to develop a strong root system.
In the second year, feed plants with a fruit fertilizer and lay straw around plants, this will protect fruit from contamination with soil,water regularly and net if need be.
Once fruit is finished, compost straw, cut off any died/old leaves as this allows sunlight into the centre, ensuring better crops the following year. Weed and balance feed and lastly, peg down any runners whilst still connected to mother plant.
I bought 12 cold runners online because its a variety ( marshmello) I cannot buy from retail and I'll not get to taste them until next year
. But I do have last years plants
.