potatoes
 

Hello,

Following the advice here I bought some seed potatoes. I found 2nd
earlies and main crop in the garden centre and took them home and
chitted them. Later I bought some 1st earlies too. All varieties are
now growing, but the 2nd earlies are taller than the 1st earlies; I
don't know if that's because they had a head start as I bought the 1st
earlies slightly later or whether that variety just grows taller
anyway? It could also be the 1st earlies are slightly more in the
shade.

I have just moved to this garden so I don't have an established
compost heap, so I have been buying compost to help with the earthing
up. I have not used any feeds, so perhaps they have taken nutrients
from the compost? What feeds do you recommend if any? I haven't done
much watering; the rain has taken care of that. So with the exception
of earthing up, they have been relatively maintenance free. What
should I be doing to them?

Finally, and most importantly, how do I know when it is time to
harvest the tubers?

Thanks.