Carrots Parsnips

I have built a 5ft by 3ft box to grow long carrots Parsnips and stump rooted carrots. I chose not to go down the sand route boring holes and filling them with the magic mix. Instead i filled the whole box with old compost from the tunnel mixed in my mixer with sand and sieved topsoil I then made holes at 1foot spacings with a long bar deep in to the subsoil underneath, these holes were filled with a mix of,
Compost 5 Litres
Vermiculite 1 Litre
sieved Bagged Topsoil 1 Litre
Vitax Q4 2oz
Calcified Seaweed 20z
Superphosphate 20z
Lime 2 oz
so we will see what the results are. I intend to cover the bed with Enviromesh to keep the Carrot Flies out hopefully.