Lowering my raised bed

[Dynamite]

so how should I lower the level of soil in the bed?
(OK, it's an academic exercise now as I can't put the soil elsewhere)

I agree you want to avoid damaging the soil structure, but I physically can't put the required level of mulch in there to meet no-dig suggestions. even putting less than 2" on was going straight off the sides.

(raising the height of the sides is not an option)

Remove some soil from the bed and dispose of. Add in humus rich material. Job done.

[Snoop Puss]

If you're putting brassicas in, don't bother to add mulch this year. They have sturdy roots and and will enjoy the hard conditions. Cover with weed membrane to block the light to the marestail and plant through that. Next year, if the marestail is still there, feed and plant something else through the membrane that doesn't mind firm ground, onions, say. Though that would leave your weed membrane pretty useless for anything else but onions due to all the holes. But that would give you another year of marestail light starvation. Plus two years of humus from the brassica and onion roots left in the soil. In between the brassicas and onions, you could consider some overwintering chard.

You might not get fantastic crops, but it would give you a bit longer to kill off the marestail while giving you something of a harvest.

Or, you turf the soil out of the bed onto a tarpaulin and mulch. But you've then got a tarpaulin of marestaily soil to deal with, plus you're still stuck with the roots lower down.

I don't know... But it seems like you can't have what you want. Which is to mulch without adding to the soil level and without removing any soil.

Sorry. I'm sure you've been pondering all the options.

[bikermike]

thanks for all the answers.

As you say, I have been through all the permutations, the question I wanted guidance on was "On the assumption I need to lower the soil, what is the least soil-unfriendly way to do it".

marestail has had 3.5 years under black plastic... I think simply leaving it to get bored on it's own isn't sufficient, where I've driven it back, it's been by a combo of covering, hoeing off the new growth and actively pursuing the roots.

also, as a personal value judgement, I don't like to use too much plastic, and certainly not growing through it (as that seems to pretty much render it un-reusable).

Anyway, as noted above, as I now don't want to put the soil anywhere else, and have had to dig into it heavily, it's all by the by.