Jennifer Schultz Nelson
Extension Educator, Horticulture
Judging by my own yard and reports from family, friends and neighbors, rabbits are wreaking havoc across central Illinois' gardens. These conniving little creatures have made gardening, especially vegetable gardening, a challenge this year.
The influx of rabbits into my garden has made growing salad greens such as spinach and leaf lettuces nearly impossible. My main vegetable garden is thoroughly fenced in, but doesn't have room right now for greens. I prefer to have my salad greens more readily accessible. In the past I had grown my salad mix near my kitchen door with a mesh fence around it, but this year the rabbits made short work of my fence and all my future salads were mowed down in quick fashion.
I could build a sturdier, more permanent fence in the area, but that would limit how I use the space. I may not always want to grow vegetables there.
A garden structure I learned about recently from Maryland Cooperative Extension Horticulture Specialist Jon Traunfeld may be just the thing I need. In his quest to encourage home vegetable gardening, Jon has published plans detailing construction of what he calls "salad tables" and "salad boxes". These are basically raised beds that are raised all the way off the ground. Anything planted in them is inaccessible to hungry rabbits in the garden.
At a recent conference I attended Jon spoke about salad tables and how the idea evolved. He had toured a local organic farm, and noted that they grew their salad mix in large mobile trays that were raised off the ground.
A unique feature of these trays was that the bottom was not solid, but mesh. This allowed water to flow freely through the system, but ultimately had a very favorable effect on the root system of each individual lettuce plant.
Because the bottom was mesh, as the roots grew and reached the bottom of the tray, they would grow through and the root tips would die back as they hit the outside air. This caused the root system to develop branches. The name for this phenomenon is air-pruning. It is much like how if you pinch out the growing tip of many plants, the plant develops more branches and a fuller appearance.
If the bottom of the trays was solid with holes for drainage, the roots would hit the bottom of the tray and follow the contours of the tray, never developing the branches. The extensively branched root system appears to be one reason the plants grown in the trays perform exceptionally well. The well-branched roots have more surface area than unbranched roots, with more opportunity to absorb water and nutrients.
Another advantage of the mobile trays was the ability to grow salad greens throughout the heat of the summer. Typically, the best salad greens come from the garden in the cool weather of the spring and fall. As summer heats up, the greens switch over to flowering mode, and start to develop flower stalks and buds rather than leaves. The leaves that are there tend to become bitter.
Unlike most vegetable crops, salad greens like lettuce and spinach can tolerate some shade. The cooler shade delays the switch to flowering, making it possible to grow good tasting salad greens even in July. The mobile trays allow the greens to be placed wherever the best conditions are, depending on the time of year.
Jon adapted what he saw at the organic farm and scaled it down for home use. The plans include the salad table, which has legs like a table, raising the bed a few feet off the ground, and its "baby" version for small spaces, the salad box, which is much smaller and doesn't have legs, but has handles so you can move it around easily. The plans are available free of charge at the Maryland Cooperative Extension Home and Garden Information Center website at www.hgic.umd.edu , fact sheet #601 "Grow Your Own Greens with Salad Tables and Salad Boxes". Click on the publications tab and look under 'online publications'.
The finished boxes are only about three inches deep. This shallow depth is adequate for salad greens. The growing media is standard soil-less mix, like what you would use in a container on your porch or patio. Unlike garden soil, the soil-less mix is light, drains well, and doesn't contain weed seeds.
The small soil volume in the boxes means that regular watering and fertilizer is essential for success. Incorporating organic or commercial time-release fertilizer into the planting bed is one fertilizing option, so is using a good balanced water soluble "blue water" type fertilizer.
Just like when growing salad greens directly in the ground, you can obtain several harvests from the salad table by harvesting the greens with scissors, then letting the plants continue to grow. This "cut and come again" method should work for at least two or three rounds in a given planting.
Compared to 'in-ground' plants, the salad tables yield more. This is probably related to the superior root systems that the salad table plants develop, plus the boxes themselves can be moved around, always seeking ideal conditions.
An added benefit of the salad table is accessibility. Obviously, this growing method makes your tasty veggies inaccessible to the rabbits. Additionally, the table can be constructed at a comfortable height for the user, making gardening less of a chore, and a lot easier on your back!
Growing crops other than salad greens is possible, but requires a deeper box to hold more soil. The plans are easily adapted, and in fact Jon wants to know about it. His contact information is listed in the salad table plans, and he asks that people share how they used the plans, improvements they made and crops they grew.