Manger Drainage and Nutrients
I’ve set up raised beds and planted up a manger at home this Spring so I can answer ‘having just done that!’ You didn’t say if your ‘topsoil’ was new or if you are using existing soil from your garden but the main thing to remember is to use good quality soil as all vegetables need a rich and balanced growing media in which to grow. If your topsoil is poor quality it will benefit from being enriched with organic matter, compost or well rotted manure. This should be done yearly to replenish the soil as it will be depleted after a long growing season.
The crops you are planning to grow all like an open soil especially carrots (these also like a sandy mix) so ensure that the soil is not compacted too and all clumps and stones are removed. You don’t have too but I also give any flowering plants a Organic Liquid Feed once a week whilst watering.
Good luck with your manger and hope you produce some quality crops.
Lynn Burton - Horticultural Advisor & Kitchen Gardener