Plants and soil types
Your favourite plants don’t seem to thrive in your garden? Check your soil- it’s structure, acidity, alkalinity and fertility have a major impact on what will or won’t grow.
Here we take a look at soil – what it is, how you can access yours and what you can grow in acid and As.
What is soil made of?
Take minerals from rocks, organic matter in the form of rotted manure and vegetation, and organisms – bugs, bacteria and worms that help to aerate and condition your garden, vegetable patch– and what you get is soil. The foundation and nutrient source for all plant life in your garden.
What kind of soil do I have?
Different geology, topography, and weather conditions mean each of us has a unique mixture of minerals, organic matter and organisms in our gardens. That said, your soil will share similar characteristics with neighbouring gardens and will reflect the general makeup of soils in the area.
Soil type Properties
Clay soil Full of minerals, this soil is fertile but quickly gets cold and waterlogged in winter, and during the summer, bakes to a crust. Sticky mud you can roll into a sausage is a clay soil.
Silt soil clay, silt is fertile, holds water and is easy to compact. Unlike sticky clay, silt soils have a silky consistency.
Sandy soil has much larger mineral grains than clays and silts. It’s free draining and thanks to the air trapped within it, sandy soil is also warmer than either clay or silt. However, it tends to be low in nutrients, dries quickly, and is often acidic. Sandy soil is gritty and crumbly in texture.
The consistency of this soil varies considerably depending on its precise makeup – some are heavy, some quite light, but all chalky soils tend towards alkalinity.
Peat soil Full of dark organic matter, peat soils hold a lot of water.
Combines elements of sandy, clay, and silt soils to produce the best of all worlds, a soil that’s moist, fertile and drains well.
Acid and alkaline soils
You can measure the acidity of your soil using a soil test kit available from all good garden centres. A pH value of 7 is neutral – less means your soil is acidic, more makes it alkaline. A soil additive may make a temporary difference to the pH of your soil, but in general, good gardeners grow the plants best suited to the soil at their disposal.
Soils which contain significant quantities of chalk or limestone have an higher pH value – they’re alkaline soils. And while adding organic matter will help balance the soil over time, you’re probably better off growing some of the wonderful plants that thrive in chalky soil:
• Lavender- wonderfully aromatic and a mecca for bees, lavender loves free-draining chalk soil.
• Honeysuckle- another bee-friendly plant that smells divine, sun loving honeysuckle thrives in fertile soil with good drainage.
Lilac- like fertile, well manured soils that drains easily. These low maintenance plants require little more than an occasional prune, and like a sunny spot in which to thrive.
• Verbascum– like light chalky soils in full sun, and will reward you with a dazzling display.
Garden soil is always in flux. Plants deplete it of nutrients, rain washes them away and even heavily amended soil will eventually revert to its natural state. You will need to amend your soil on a regular basis. How often will depend on the soil you are starting with. Once you get to know your garden soil, you will have a better sense of what amendments your garden will need.
The best practice you can get into is using organic matter in your garden whenever possible, and the easiest way to do that is to start and use a compost pile. Put those pulled weeds, vegetable peelings and garden debris to good use. You probably won’t be able to make enough compost for all your needs, but it’s a good start and it’s free.
Composted materials won’t necessarily add much in the way of nutrients, but they will encourage a balanced ecosystem that will keep the nutrients and soil pH in check while they improve the texture and drainage of the soil.
Alkaline Soil and Plants That Don’t Mind Alkalinity
Soils with a pH level that is higher than 7 are said to be “alkaline.” Such soils are suitable for growing plants that thrive in a “sweet” soil, as opposed to a “sour” or acid soil. If soil pH needs to be raised (that is, the ground is not alkaline enough), apply garden lime.
Fortunately, just as there are plants that like acidic soils, which give you planting options on sour ground (when you can’t — or do not want to — raise the soil pH), so there are plants that like alkaline soil (or, at least, do not mind growing in it).
Plants That Grow Well in Alkaline Soils
The list below does not pretend to be exhaustive. But it gives you enough options to begin planning to landscape on ground that is alkaline. You will find perennials, vines, shrubs, and trees on the list. A plant’s inclusion on this list does not necessarily mean that it needs or prefers to grow in an alkaline soil (although it might), only that it will, at the very least, tolerate alkalinity:
Perennial: Black-eyed Susans, Catmint (Nepeta × faassenii)
Centaurea Columbine Daylilies
Delphinium Easter lilies (bulb plant)
Festuca glauca ‘Elijah Blue’ (ornamental grass)
Hibiscus syriacus (Rose of Sharon)
Jacob’s ladder (Polemonium caeruleum)
Lenten rose (Helleborus orientalis)
Maiden grass (Miscanthus sinensis, an ornamental grass)
Maltese cross (Lychnis chalcedonica)
Pasque flower (Pulsatilla vulgaris)
Red hot poker (Kniphofia), Salvias, Shasta daisy
Boston ivy Kiwi (Actinidia kolomikta) Vinca minor, Virginia creeper, Honeysuckle
Shrubs(Bushes):ArborvitaeBuxus Sempervirens ‘Suffruticosa, Euonymus fortunei ‘Emerald Gaiety’, False cypress (Chamaecyparis)
Forsythia, Golden privet (L. ovalifolium ‘Aureum’)
Lilac bushes, Rose of Sharon bushes Smooth sumac (Rhus glabra), Viburnum
Yucca filamentosa, Ginkgo biloba, Mugo pine, Lantana, Oleander, Ixora, Casuarina humilis, Tamarix, Pittosporum
Trees:, Casuarina cristata, Erynthrina (Coral tree), Euphorbia leucocophala, Caesalpina pulcherrima, Justicia species, Jacaranda mimosifolia, Murraya paniculata, Plumeria (Frangipani), Tibouchina, Peltophorum, (Yellow Ponciana), Guava, Fig, Syzygium samarangense (sweet water apple, love apple, jambu fruit)
Vegetables And Herbs
Ugu, Fluted pumpkin –Telfairia occidentalis, Okra, Cabbage
Parsley, Oregano,Thyme, Garlic,Tomato, Potato (Irish), Cauliflower, Corn.Spinach, Beans, Beet, Brussels sprout
Cantaloupe, Celery, Chinese cabbage, Lettuce, Onions,Pea
Watermelon, Collards, Spinach, Pepper garlic
Where to Go From Here
Some annuals can also be grown in an alkaline soil without difficulty, including Calendula, bachelor buttons, and sweet alyssum. Mix some annuals into your perennial flower borders to achieve the landscape color scheme that you are seeking.
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