I'm just learning about hugelkultur and I'd like to try making a bed for springtime. In the second, and subsequent years, how do you prepare the beds for planting in spring, since you can't really dig them or till them? They'll probably be covered with weeds.
Also, people talk about building up the beds a little more each year, but how do you do that? Do you take dirt from somewhere else and put on top? I just have a medium sized suburban yard, and buying dirt by the bag is expensive.
I thinkthe answer to your question of how to build them up is: mulch. The mulch will break down into soil, and will impart valuable nutrients, while smothering the weeds. Or so I've heard. This is my second year with hugels, and I encountered the weed problem the first year because I didn't mulch. This year, I raked up leaves from under my trees and clippings from my lawn, and put down about 3-5 inches of that on top of my hugel. I don't know, however, if that's too much or too little mulch. I'd love to see what the experts have to say!
B aware, though, that if you live in wet area prone to slugs, the mulch will make a great home for them. We ended up having to get ducks for that reason--slugs ate everything!
When you finish harvesting your crops from the hugel, just chop what's left and let it lay. If you see settling (depressions or even craters) happening, just fill in with compostable materials. If you want to add overall soil depth then I would use finished compost or at the end of the growing season cover the whole mound with compostables and perhaps put on a layer of mulch. I personally like to use old carpet scraps to cover a mound that I am composting in place, it holds more of the rains in and prevents rains from washing away the materials I have placed there to turn into compost. In the spring I remove the carpet(s) and plant.
The biggest cause of failures, IMO, is not building them in layer fashion. I have a few neighbors that have tried growing mounds but they just put in all their wood at once then covered them with the soil and compost they moved out of the way to build the mound. If you are building a standing wood type mound, it is important to fill the gaps between the rotting wood with compostable materials then you put the cover on. If you are building horizontal mounds, dig down to the sub soil, save the good dirt off to the side for the cover, lay in the largest diameter logs then a layer of leaves and other compostable materials (straw, grass clippings, wood chips or saw dust, ect.) then lay on the next layer of wood which should be slightly smaller in diameter than the first layer, continue in this manner until you have the mound built up to the height you desire. I use kitchen scrap and butchering left overs as part of the first wood cover layer since animals would be hard pressed to get at them when the mound is finished. This particular layer also adds valuable minerals from the bones. Once you have built the mound to the height you want, you are ready to lay on the cover. I like to mix my cover soil with an equal volume of finished compost before putting it on the mound, the last step for me is to put on a layer of some sort of mulch. then I plant my cover crops, I like to use low growing cover crops so that when I come in to plant my squash and other food crop plants. The food crops will shade the cover crop and stunt it by taking away the sunlight. At the end of the growing season I chop and drop what is left of the food plants. This year I used Kale as a winter crop on two mounds, this way I am getting tasty greens all winter and in the spring I can cut them down and plant my spring/summer food crops.
Hope this a good enough explanation, if not let me know and I will delve deeper for you.