Manure Tea

I am growing cabbages (Hispi & Monarchy F1) indoors from seed.
I will plant them out next month.
I have purchased soil for the raised beds.

I am concerned however that the nutirients in the soil will not last beyond 3 weeks.
I have read about Bone meal being good for cabbages but this is low in Nitrogen, although good for root growth.
I would also like to prepare my own manure tea.

Can you advise me on the following plan:

1. Mix in some organic matter 2 weeks before planting out.
2. Mix in Bone Meal just prior to planting out.
3. Add manure tea every week.

If this process is wrong then I would appreciate your input.
Also, do I add maure tea to the soil only or can it be sprayed over the veg.

Thank You

As Chris says - they don't like it hot. If you have to germinate them indoors, as soon as they show - get them somewhere cooler like a cold frame or unheated greenhouse otherwise you'll end up with very weak plants

Don't over feed cabbage, you could end up with a lot of open leaf growth, rather than a solid heart.

Make sure the soil you plant them in is well compacted - they don't like it open.

I think you're a bit too concered about feeding them, you could do them more harm than good. Nutrients in soil I hope last beyond 3 weeks.