Fruit is a long-term planting, and the soil you plant it in is the soil it will live in for years — a decade or more for a tree, and many years for a berry bush. That makes soil preparation the most important job in fruit growing, and the one that is hardest to fix later. You can prune a tree next year, you can water it next week, but you cannot easily change the soil under a tree that is already planted. Get the soil right before you plant, and everything after it gets easier.
The first step is to know what you have. A soil test tells you the pH and the nutrient levels, and it is the cheapest insurance in the garden — a simple kit from a garden centre, or a laboratory test through your extension service, will tell you more in a week than years of guessing. Fruit is fussy about pH in a way vegetables are not: blueberries need strongly acidic soil, apples and pears want slightly acidic to neutral soil, and citrus wants neutral to slightly acidic soil. Plant a blueberry in alkaline soil and it will yellow and fail no matter how well you feed it.
The second step is drainage. Fruit roots need air as well as water, and soil that stays waterlogged will rot the roots of almost any fruit tree. If your soil is heavy clay that holds water, or light sand that dries out in days, you need to improve it before you plant — and the improvement is the same in both cases: organic matter. Compost opens up clay so it drains, and it gives sand something to hold water and nutrients. There is no fruit soil problem that compost does not help. If you are unsure about a variety, a spray, or a diagnosis, check your local extension service — its advice is matched to your climate and soil.
Test first: pH, texture and drainage
Start with a soil test. A pH test tells you whether your soil is acidic, neutral or alkaline, and a full test tells you the levels of the major nutrients. Most fruit wants a pH between 6.0 and 6.8 — slightly acidic to neutral — with blueberries the exception at 4.5 to 5.5, and figs and grapes tolerating a little alkalinity. If your soil is too acidic, garden lime will raise the pH over a season; if it is too alkaline, sulphur will lower it, but slowly, and for blueberries it is usually easier to grow them in a container or a raised bed of acidic compost than to fight alkaline soil. Test the drainage with a simple hole test: dig a hole a foot deep, fill it with water, let it drain, fill it again, and time how fast the second filling drains. If it drains in a few hours, the drainage is good; if it is still there the next day, the soil is waterlogged and you need to improve it or plant on a mound. The soil volume calculator can help you work out how much compost or soil a planting area needs.
Improving clay soil for fruit
Clay soil is fertile but heavy: it holds water, sets hard in summer, and suffocates roots in winter. The cure is organic matter, added in quantity and over time — a thick layer of compost dug in before planting, and a mulch of compost every year after. Gypsum is sometimes recommended for clay, and it can help a clay that is high in sodium, but for most garden clay, compost is the real answer. Do not add sand to clay: sand plus clay makes something close to concrete. Plant fruit on a slight mound or a raised bed if the clay is very heavy, so the roots sit above the wettest soil, and choose rootstocks and varieties known to tolerate wet soil — plums, for example, tolerate heavier soil than peaches or cherries. Fork the bottom of the planting hole so water can drain through, and never dig a hole in clay and fill it with compost alone, because the hole becomes a sump that holds water around the roots.
Improving sandy soil for fruit
Sandy soil is the opposite problem: it drains fast, dries out in days, and holds almost no nutrients. The cure is the same — organic matter, in quantity. Dig in as much compost or well-rotted manure as you can before planting, and mulch thickly every year, because the organic matter is what holds water and nutrients in sand. Water sandy soil more often and in smaller amounts than clay, and feed little and often rather than in one big dose, because nutrients wash through sand quickly. Strawberries, figs and grapes tolerate sandy soil better than most fruit, provided they are watered and mulched, while apples and blueberries struggle in sand unless it is heavily improved. A windbreak helps too, because sandy soil dries fastest in a drying wind. Over several years of compost and mulch, sandy soil becomes a good fruit soil — it just takes longer than clay to get there.
The right soil for each fruit
Apples, pears, plums and cherries want a deep, fertile, well-drained loam, slightly acidic to neutral, and they will tolerate clay if it is improved and drained. Peaches want a lighter, well-drained soil and hate wet feet more than almost any other fruit tree. Figs and grapes tolerate poor, stony soil and even a little alkalinity, and they often fruit better in soil that is not too rich — too much fertility makes them grow leaves instead of fruit. Blueberries are the specialist: they need acidic soil, a pH of 4.5 to 5.5, and a soil rich in organic matter that stays moist. If your soil is alkaline, grow blueberries in a container or a raised bed of ericaceous compost, and water with rainwater. Strawberries want a rich, moisture-retentive loam, and they are the fruit most tolerant of a heavy soil, provided it does not waterlog. Citrus wants a free-draining, slightly acidic soil and hates wet feet, which is why citrus is so often grown in containers. Raspberries want a moist, fertile soil and will fail in dry sand or waterlogged clay.
Preparing the planting hole and the ground
Prepare the ground weeks before you plant, not on the day. Clear the weeds, dig in compost over the whole area rather than just the hole, and let the soil settle. For a tree, dig a hole twice as wide as the root ball but no deeper than it, so the tree sits at the same depth it grew at before — planting too deep is the commonest cause of a failing fruit tree. Break up the sides of the hole with a fork, so the roots can grow out into the surrounding soil rather than circling in a smooth-sided pit. Mix a little compost into the backfill, but do not fill the hole with pure compost, which slumps and holds water. After planting, water thoroughly, mulch with three or four inches of compost or bark, keeping it away from the trunk, and stake the tree if it needs it. For berries, prepare the whole bed rather than individual holes, because their roots spread widely and they will live in that bed for years.
Keeping fruit soil healthy year after year
Fruit soil is not a one-time job: it needs feeding every year, because the tree takes nutrients out with every harvest. Mulch with compost each spring, and the soil life will do the rest — worms, fungi and bacteria breaking the compost down and making its nutrients available to the roots. Grow a green manure or a cover crop such as clover under and around fruit trees in the spaces you do not need, and let it fix nitrogen and protect the soil. Avoid digging around established fruit roots, which are shallow and easily damaged — mulch on the surface instead. Do not use a weedkiller around fruit trees, because it can damage the roots and the soil life. Test the soil every few years, and adjust the pH if it has drifted. And keep a note of what you added and when, so you can see what the soil responds to over time.
Frequently asked questions
What pH does fruit need?
Most fruit wants a pH of 6.0 to 6.8, slightly acidic to neutral. Blueberries are the exception and need 4.5 to 5.5, strongly acidic soil.
Can I grow blueberries in alkaline soil?
Not in the ground — they will yellow and fail. Grow them in a container or a raised bed of ericaceous compost, and water with rainwater if your tap water is hard.
How do I improve clay soil for fruit trees?
Add organic matter — compost dug in before planting and a compost mulch every year. Do not add sand to clay. If the clay is very heavy, plant on a mound or in a raised bed.
Should I put compost in the planting hole?
Mix a little compost into the backfill, but do not fill the hole with pure compost, which slumps and holds water. Better still, improve the whole area before planting.
Why is my fruit tree failing in wet soil?
Fruit roots need air as well as water, and soil that stays waterlogged rots the roots. Improve the drainage with compost, plant on a mound, or choose a variety and rootstock that tolerates wet soil.
Soil preparation is the quiet work that decides the next decade of your fruit garden. Test it, improve it with compost, plant at the right depth, and mulch it every year. For the soil needs of individual fruits, see the growing guides, including blueberries and apples, and check your planting calendar for timing in your zone.