by Margie Siegal
In order to have happy, healthy plants, you need to start with healthy soil. Think of your garden as a welcoming home for your seeds and plants. You want to give them the best possible start, so they will grow big and tall for you, and produce great vegetables.
Plants absorb nutrients and water through their roots. In order for plants to do this effectively, the soil needs to be loose enough to easily push roots through, it needs to have consistent moisture levels, and have the right acid/alkaline balance. Nutrients in the soil have to be in the right balance. Most vegetable plants are pretty forgiving, so none of this has to be perfect, but the better you treat your plants, the better they will perform for you. Let’s look at each of these items in turn.
Soil Texture
There are large areas of Alameda that have sandy soil, but other areas have the kind of clay soil that is common to most parts of the East Bay. In order to find out what kind of soil you have, go out in the yard and grab a handful of wet soil. If it feels gritty and falls apart easily, you have sandy soil. Sandy soil is easy to dig in, but fertilizer washes into the groundwater every time it rains, and water just drains through, making it difficult for plants to catch before it sinks into the earth. If your handful of wet soil sticks together and to your fingers, you have clay soil, which holds water, but is too dense for plants to grow roots in. What you want is soil that has a nice crumbly texture and a good earthy smell.
You fix either sandy soil or clay soil the same way: by adding lots of organic matter. Finished compost is an excellent soil amendment, the easiest to find, and usually the cheapest. Possible sources of compost are:
- Ploughshares Nursery, 2701 Main Street, at Alameda Point
- Encinal Nursery, 2057 Encinal Ave., Alameda
- Waste Management/EarthCare (San Leandro)
- Bee Green (East Oakland)
Acid and Alkaline balance
Most vegetables like soil that is neutral – neither acid nor alkaline. Acid and alkaline is measured on a Ph scale. Low numbers are acid, 7 is neutral, and higher numbers are alkaline. You can buy a test kit that will measure both plant nutrients and Ph for under $20. You can also get a Ph meter with a probe that you stick in the soil (also about $20). If you have children, testing soil is an excellent science project.
If you have acid soil, add lime, obtainable at any plant nursery. The information sheet that comes with your test kit will explain how much to add. It is very unusual in the Bay Area to have soil that is more than a little alkaline.
Loosening up the Soil
Your gym is closed, so you need a workout, right? Put on your loudest gym clothes and your gardening gloves, pull on a pair of rain boots and grab a shovel and start digging. Dig a trench at one end of your garden plot and put all the weeds and grass in the green bin. The trench should be a foot or so wide and at least a foot down, eighteen inches is better. Then dig out the next foot wide space next to the trench you just dug. Dump the soil from trench #2 into trench #1 and mix in your compost – as much as you can find, up to a pile the size of the trench and six inches deep. Also add lime and fertilizer if your soil needs it. Keep going until you have all of your garden area dug out, then put the dirt from the first trench into the last trench. This is known as double digging and is great cardiovascular exercise. DON’T step into your garden area if possible – you want that soil nice and fluffed up.
Adding Nutrients
The three big nutritional needs for garden plants are nitrogen, potassium and phosphorus. Plants also need other nutrients in smaller amounts. Do a soil test before you add anything but compost. I sent a sample of my soil to a test lab and found I was off the chart on potassium. I had been getting loads of free horse manure for the garden, which is high in potassium (and also acid). Your soil test kit will tell you what you need to add.
These four steps will get your garden ready for a year of happy plants.