Soil pH

pH is measured using a scale that ranges from 0 to 14, where 7 is neutral.  Most plants grow best in soil that has a pH of 6.5 to 7.0, although some plants prefer soil that is slightly acidic or alkaline.

If your soil is too acidic or alkaline for the plants you have chosen to grow, you may notice that their growth is stunted, they have yellow spots on their leaves, wilting leaves, blighted leaf tips, or poor stem development.  Moss and weeds thrive in acidic soils.

There are many types of home soil test kits and devices, such as the meter photographed above, which you can use to assess the pH of your soil.  You can also perform a simple test using baking soda and vinegar, if you want to test whether your soil is acidic or alkaline (but not to which degree):

  1. Obtain two scoops of soil from your garden.
  2. Add vinegar to the first scoop.  If the soil begins to bubble, it’s alkaline.
  3. If there is no reaction with the vinegar, add distilled water and baking soda to the second scoop.  If the soil begins to bubble, it’s acidic.
  4. If both tests fail, your soil is neutral.

Plants that like or tolerate acidic soil (pH < 7.0)

  • Blueberries
  • Cranberries
  • Currants
  • Garlic
  • Gooseberries
  • Parsley
  • Peanuts
  • Peppers
  • Potatoes
  • Radishes
  • Raspberries
  • Rhubarb
  • Strawberries
  • Sweet Potatoes

Plants that like or tolerate alkaline soil (pH > 7.0)

  • Asparagus
  • Beets
  • Cabbage
  • Celery
  • Cauliflower
  • Carrots

Altering the pH of your soil

You may need to work additives into your soil if the pH is not optimal to the plants you wish to grow.

  • To increase your soil’s alkalinity, you can add limestone, ground oyster shell, gypsum, or wood ashes.
  • To increase acidity, add coco peat or pine needles.  Peat moss is a common additive, but it is one you may want to avoid.  When peat moss is harvested, the delicate balance of the bogs in which it is found is often damaged.



Starting seedlings using soil blocks

Rather than using seed trays and pots to start seeds, you can use a mold to create soil blocks.  Soil blocks are squares of dirt that are made using a specific mixture of soil which holds it shape.  These blocks are placed on a tray in a grid; one seed is placed in each block.


Large and small soil block molds, and a set of four small soil blocks


Soil blocks offer several advantages over containers:

  • It is easier to water trays of soil blocks; just pour water into the tray and it will spread upwards into each block.
  • Seedlings are unlikely to become root-bound, because they are surrounded by air.
  • When you transplant your seedlings, their roots aren’t disturbed, because you can simply plunk the plant and its soil block into its new location.  You don’t need to tear it from its plastic container.
  • You’re not wasting plastic pots and containers, which often become fragile and useless after a couple of seasons.

How to use soil blocks

Purchase soil specifically made for this purpose, or make your own by mixing three parts finished compost with one part garden soil and four parts coco peat.  Potting soil is too light; other soils may be too dense.  You need a soil mixture that will retain its shape, hence the recipe above.

Add a fair bit of water to the soil; it should be quite wet, but it should hold its shape.  Maybe if you have kids, they would like to help with this step.  🙂

Put this mixture in a shallow tub and press the mold into it using the flange.  You may need to twist the mold or push it into the mix a few times before its blocks are full (check the bottom to ensure it’s full before you empty it).  Press the mold onto a sturdy, airtight tray and release the blocks.  Most molds make a slight dimple within the centre of the block; into this, place a seed, then cover with a bit of soil as needed.

Please the tray in a sunny or artificially lit area.  Keep the blocks moist by filling the tray with water.

The Lee Valley molds linked to above come in two different sizes–so when a seedling outgrows its small soil block, you can create a larger block to insert it into.

Composting 101

Most Canadian municipalities now offer curbside collection of yard and kitchen waste.  Some even allow you to pick up free bags of compost in late spring.  So why make your own compost onsite?  Aside from avoiding the costs associated with purchasing compost, you can control what’s feeding your plants.

Composting kills many of the weeds, seeds pests, and diseases that may be present in your food and garden waste, but it retains most of the nutrition.  It’s recycling at its finest!

But compost stinks, doesn’t it?  And it attracts maggots?

You can avoid having stinky and maggot-infested compost by excluding animal products (meat and dairy) from your compost.  Eggshells are fine.

Many of the commercially available compost containers are made of plastic, which contains vents but are not very breathable.  The compost does tend to smell when you open the lid.  Once the lid is closed, they’re usually fine.

If you place your compost in a container made of wood or other natural materials that are spaced to allow air flow, and add grass clippings or other yard waste over any particularly fresh kitchen scraps, it should not smell.  You may also want to avoid using manure as an activator (see more in hot composting, below).

But I don’t have a backyard

Worm farms are great.  The worms can’t eat all of your compost, but they can eat some of it.  They’ll create beautiful dark earth for you.  They don’t smell and you don’t need to take them for walks.  You may be able to purchase worm farm kits locally.

Types of composting

There are two main types of composting: cold and hot.  Cold composting is basically the “throw in what you have” method.  The compost does not heat up enough to cause rapid decomposition, so some weeds seeds may not be killed, and the process takes longer.  Hot composting is like making a lasagna; you have to have enough ingredients on hand to make one set of layers, because you don’t want to cook it with the sauce on the top.  If properly assembled and monitored, it will typically produce compost in two months rather than the year or more needed for cold compost.

The specific details of how much material you should add will vary according to the type of container and composting you choose.  As always, what follows are guidelines.

Cold composting

Cold composting is the easier option, and it also produces more fertile soil than hot composting, because the material does not get hot enough that all of its nutrients are broken down.  Some are retained and then released when the compost is added to the garden.  Worms find their way into the compost to help break down cold compost material.  To accelerate decomposition, consider cutting materials into small pieces.

The layers are simple:

  1. On the bottom, add sticks to let ait infiltrate the compost.
  2. Follow this by garden waste, grass clippings, and kitchen waste as they are produced.
  • You can add straw, or straw-like plants, to aid with air circulation.
  • You can add manure to the compost to act as an activator to increase heat (and therefore the rate of decomposition).

Once or twice a year, turn the pile to improve decomposition.  I use two side-by-side wooden compost bins, so I turn them in the fall once the garden is almost empty, and often in the spring.  One bin contains last year’s compost, and the other one contains the current year’s compost.  Both are at least half full when I turn them.

Turning does not involve rotating the bins, but its contents. I transfer the intact plant material from the first bin to the second, removing the composted dirt and putting that in the garden.  Then I move the intact plant material from the second bin into the first bin, adding a bit of composted dirt between layers, and move the rest of the composted soil from the second bin to the garden.  I am left with one full bin of rotated compost and another that is empty and ready to accept new spoils.

Hot composting

Hot composting relies on manure to heat compostable materials up so that they break down quickly and thoroughly.  Roots and woody materials are thoroughly broken down, and weed seeds and diseases destroyed.  Hot composting is not an ideal solution for small lots because when manure is exposed to high temperatures, ammonia is released into the air.  In other words, it can be smelly.

The layers are more complex.  You must complete steps 2-5 each time you top up the compost.

  1. On the bottom, add sticks to let ait infiltrate the compost.
  2. Add 4-6 inches of rich green organic matter, such as grass clippings and kitchen waste.
  3. Add 1 inch of cow, sheep, or horse manure.
  4. Add 1 inch of soil.
  5. Add 4-6 inches of brown organic material, such as straw.
  6. Repeat steps 2-5, ensuring that 5. is always on the top.
  7. Once the material has begun to decompose, don’t add any additional layers.  Check the temperature, which should be between 54C and 60C.  If it gets waterlogged, cover it with a waterproof tarp.  If it is too dry, water it.
  8. When the temperature drops, turn the pile.
  9. Repeat the process until it is decomposed.

Seed starter

You can use your compost to create soil to use to start your seeds.

Remove some of the compost you created, and set it in a pile for at least a year.  Store it in cloth or burlap bag for the winter in a cold room or root cellar so that it retains its moisture.  You may wish to run it through a sieve before you use it to remove any sticks or large particles.

That seedy neighbourhood

AKA, what can I GIMBY?

Before we rush out to get some seeds, we need to consider our growing conditions, such as the amount of sun and type of soil.


If you have full sun, you are lucky. 🙂
If you have a lot of shade–well, here are some plants for you:….


Most plants do well in loam soil. Loam is a combination of sand, silt, and some clay. It’s porous enough to allow water to be absorbed and roots to grow, and contains more nutrients and humus than sandy soils. Silt is the second best choice. It’s also suitable for most plants.
If your soil has a high proportion of clay, it’s heavy and not very porous. Vegetables like broccoli, brussel sprouts, and cauliflower may do well, but, over time, you may want to add compost and other materials to it to improve it:….
If you have sandy soil, then root vegetables are your friends: carrots, turnips, radishes, onions, and garlic. Sandy soil tends to dry out, blow away, and leach nutrients. You’ll need to add a lot of compost, mulch, and other organic matter to it if you want to improve it.


Do you have any fences that plants such as beans and cucumbers can climb? How about an deck on which you can place some herb planters? Herbs like oregano and mint can run wild if put in a garden; it’s best to keep these contained.


Previously, we mentioned plant hardiness zones, which you can use to determine if a vegetable or fruit will thrive in your climate. But, you don’t really need to refer to these zones if you buy from your local seed supplier’s catalog. If you’re shopping on the internet, by all means, keep your plant hardiness zone in mind!
Your local seed supplier grows plants on site, and offers only those varieties that thrive where you live. They may also have tips for specific plants or varieties. Seeds sold in chain stores may be bought for entire regions or countries, rather than being selected for specific climates.
Here’s where we get our seeds:
  • Local seed suppliers that specialize in organic heritage varieties.
  • Seed exchanges, which you can attend to exchange or buy seeds from local gardeners. Here in Canada, now is the time to go!
  • Last year’s plants. Peas, beans, squash, corn, peppers–many plants produce seeds that are easy to collect and keep for the next year.
Happy seed collecting!