A South American engulfed my resting vegetable beds

I had put my veggie beds to rest for the winter. What could go wrong?

I knew we were going to be out of town for the first three months of 2020, so I did not plant our normal winter crops. After the last summer/fall crops in three of the beds, I weeded them trying to disturb the soil as little as possible and then covered them with a four-inch layer of pine needles. (6 reasons to use pine needle mulch in edible gardens) In two of the other three beds had the native salvia and other wildflowers growing, so I did some light weeding and left them alone. In the last bed I planted some wildflower seeds and I'll cover this bed in my next post.

So in those three beds, a visitor from South America came calling...

This innocent-looking plant is a monster!

The native range for this oxalis is shown in green while the purple areas show where it's escaped. 

Look how pretty the pink woodsorrel (Oxalis debilis) is. It's been a frequent weed in the edible beds because it loves the disturbed soil, but I have never been too concerned about it before, and over the years, I even added it to pestos and salads for its sour tang. (You don't want to eat too much of it, though because it contains oxalic crystals, which are irritating to our digestive systems. Spinach also contains these crystals which is why we add vinegar or cook them.)

But while we were gone, the oxalis formed a solid mat in those three beds that I'd put to bed for the winter.

Wow! The oxalis formed a solid mat on three of my resting vegetable beds.

I expected some weeds, but not this... Time to get to work!

I scooped out sections of the oxalis mat a garden fork so I could shake off the soil and keep the plants in one piece. I pulled out the pine needles from the plants when possible. It was a tedious process, Then I scraped the soil away from these raised beds down to the ground level and removed more oxalis bulbs and pieces that were deeper.

The oxalis had become entangled in the pine needles. I pulled out the pine needles so I could use them again.

Here's the underside of a scoop of the oxalis, which reveals the bulbs and bublets. 

Trying to extract  the mat of oxalis to ensure that the bulbs were kept intact was not easy because at this stage, most the bulbs had shed their outer skins and the tiny bublets were prone to falling away to start a whole new generation of these aggressive plants.

After removing the oxalis, it was time to prepare the bed for planting.

Adding a layer of leaves to enrich the soil and to retain moisture.

After spreading out the leaves evenly, I shoveled a layer of soil on top.

I scraped away the soil from half of the bed down to the ground level and removed remaining oxalis bulbs and pieces from deeper in the soil as I spotted them. I raked some leaves from the yard and added about three inches on the bed. This leaf layer will help retain moisture and add humus to the soil. I shoveled the removed soil back in place and repeated the process for the other end of the bed.

The hydrophobic soil needed to be carefully wetted so the seeds would be able to germinate.

Building swales to prepare for okra crop and wetting the seed planting sites at the corners and intersections around the edges of the swales.

The soil was so dry that it was hydrophobic, so I spent an extra day working to get the soil wetted with rain barrel water so the seeds would have nice even moisture so they could germinate and get a good start. It's important to use rain barrel water because in organic gardening, we want all the soil microbes, but water from the faucet includes purification chemicals so we don't get sick from the water. Those purification chemicals will reduce the population of soil microbes. Learn more by reading my post, Dealing with hydrophobic soils.

On one end of the bed I created four swales for my okra crop. This creates nine planting sites for the seeds at each intersection of the raised beds and nine to twelve okra plants is plenty for the two of us. The swales will make it easy to water the okra and over the next week or so, I will add a bucket of kitchen scraps in the bottom of each swale to add more nutrients. Those scraps will have plenty of time to decompose before the okra roots are long enough to reach the bottom of the swale. And since the extra irrigation will be in the swales, the roots will go in that direction. One advantage to this arrangement is that there are very few weeds outside of the swale areas.  Learn more by reading: Okra swales and Trench composting in the vegetable garden.

Okra swales at one end and two wide rows for New Zealand spinach on the other.

After the wetting treatment, the seeds were planted and pine needed were added in all the non-growing areas.

If you need some guidance for Florida
vegetable gardening, because
it is different here, here's a link. 

Lessons learned:
- When it comes to oxalis, light weeding is a wasted effort and pine needles are not a deterrent.
- I will be less tolerant of the beautiful oxalis from South America in and around our edible beds.

I hope you are working on your warm-weather crops,  because every pound of food you grow and harvest offsets up to two pounds of greenhouse gas emissions. 

Green Gardening Matters,
Ginny Stibolt