Raised bed soil mix

peteski2011

Hi 

I'm about to build a raised bed this weekend 3m by 1.5m and about 16 inch deep. The plan is to use some of the relatively heavy and probably poor topsoil from our garden (being dug for a patio) along with something else to break it up and add nutrient. The problem is I don't know what to add or how much. I was thinking of going 50/50 garden soil with something but there are so many composts and mulches and mushroom this and that I don't know where to start! We are aiming to grow veg and begin planting in March so I'll need something that's ready to go. I've read other threads on here but suggestions like adding horse manure etc that hasn't rotted down isn't a possibility (I've gleaned that much at least!)

Please could I have some advice? (Apologies if this is in the wrong section.)

Thanks 

BobTheGardener

I would recommend some commercial bags of 'farm yard manure' from a garden centre.  The manure in those is already well-rotted and free of weed seeds.  If you have enough topsoil, a 75% topsoil and 25% FYM mix would be ideal, finishing with a 2" layer of manure mulched on top.and left for the rest of the winter.  Come planting time, it will have broken down nicely.  Don't use manure in beds growing carrots/parsnips though or they will fork.

peteski2011

Hi BobTheGardener thanks very much for your reply. We had planned on carrots so should I just not put the 2inch top layer on? Also when would you recommend planting should begin please? Apologies completely new to all of this so have little to no clue!!  

BobTheGardener

Unfortunately, carrots will fork even with the manure mixed well in, mainly in this first season after applying.  After that you should be ok as the worms etc. will have broken it down.  However, carrots prefer a fine, sandy soil so what I do is mix in sharp sand and pre-used multi-purpose compost (from last years tomatoes etc) to the carrot and parsnip beds.  It's best to rotate your crops and not grow the same things in the same beds every year (to avoid pests and diseases bulding up), so next autumn mulch all of the beds except the 'next' carrot bed with manure again. You won't need to provide any extra plant food for your crops if you grow them like this.

BobTheGardener

Hi again @peteski2011 I forgot that you asked about planting dates.  The trick here is to not to sow stuff too early as cold, wet conditions will make most seeds rot in the soil before it is warm enough for them to germinate, so check the seed packets dates but sow towards the middle to end of the recommended dates.  Plants from later sowings usually quickly catch up with earlier sowings anyway and in my experience the uninterrupted growth produces better plants and crops.  If you have a greenhouse then you can start some things off earlier in modules (but not carrots or other roots veg as this also makes them deform.)  I usually don't sow carrots until April or later.

peteski2011

hi @BobTheGardener thanks so much for your advice. I'll make sure to follow it and hopefully we'll see some success! best regards