i planted 18 tomato plants and only 3 have come up it was frosty for the first week but after that 3 grew there small about 5cm high but i just wonder why 3 have come up and 1 havent

Do you mean you sowed tomato seed Callum and only three germinated? Where do you have these little seedlings and where are you in the country, it makes a big difference. If you sowed them outside and then had a frost your lucky any of them grew.

yes i do mean sowed and england,felixstowe and yes it was quite cold a week after i sowed them yes

Even in the south it is safer to sow the seed in a cool greenhouse and then plant out once the plants have been hardened off and are about 6 inches tall.

ok thank you in future i will do