Tomato care

You can start hardening them off during the day about the middle of May, and plant them outside after the last frost - probably at the start of June.

This is assuming you're not putting them into a greenhouse or similar.

I won't be starting my tomatoes off for another month or so.

  Yes, I only have a little plastic greenhouse so can't use a proper greenhouse to get a head start.

I've learnt the hard way that if you start off too early, you end up with leggy plants on windowsills for absolutely weeks.  I reckon about 4-5 weeks is enough to give them time to get started and grown enough before planting out.