Oxalis is all around my garden, I have tried many different products, which both are affective for a short time but it comes back as thick as ever. I put weed mat down covered with pea straw but it grows through that as well. What else might work? I have thought about digging plants out sieving the soil to get rid of the wee bulbs.
Oxalis is a bulbous weed which grows under the ground level so covering it doesn’t work. It is very problematic once it is in your garden as the bulbs multiply and spread easily. To get rid of oxalis chemically would affect the soil very badly and it is not recommended, especially in areas where you are growing edibles. Unfortunately, like you have mentioned, the only way to get rid of oxalis is to remove all of the bulbs by hand.
To do this, first divide the area up into sections then dig down 20-30cm and sieve the soil to catch all the bulbs. Admittedly, it’s a tedious task but well worth doing. Alternatively you can dig up the area, pen it off and put chickens in there. Once all the bulbs have been removed, replenish the soil with Daltons Compost and Daltons Big Value Blood & Bone.
If you decide to start over your vegetable garden somewhere else on the property don’t transplant the soil as it will only take a few bulbs to start the problem again!