How do I plant walnut trees so they all establish evenly?

Planting looks like the simplest job in orchard establishment, but it is the job where small, repeated mistakes become permanent.

A block where every tree sits at the right depth, with its roots spread and the soil firm against them, grows evenly. Its trees start to bear a crop at the same time. A block that is planted quickly and carelessly has weak trees scattered through it for the rest of the orchard’s life. You will never know exactly why.

Three things decide the result: the condition of the trees, the condition of the soil, and the care taken at each individual tree. Nothing on this page is difficult. All of it is easy to skip when there are eight hundred trees to plant and it is getting dark.

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When to plant

Plant bare-root trees (trees supplied without soil around their roots) while they are dormant (in their winter resting period, without leaves). Plant before the buds start to grow. The right window depends on your winter, not on a date copied from another country.

• Where winters are mild and the soil stays workable: plant as soon as the trees arrive. Roots begin to establish before the tree comes into leaf, which gives you a stronger first season.
• Where the soil freezes deeply: wait until the risk of a hard freeze reaching the roots has passed. Frost lifts newly planted trees out of the ground and kills them. In these regions, early spring is safer than early winter.
• Never plant in midsummer. Heat and sunburn on a young trunk with no established root system cost you trees.

As a guide, growers in mild-winter regions plant from November through to the beginning of March. It is a mild-winter window, and it is the wrong window for eastern Turkey, the Caucasus or Central Asia. Your own soil temperature, your freezing risk and your soil condition decide the day.

The go/no-go check on planting day

Make the go/no-go decision (plant today, or do not plant) before the crew starts. Make it again if the rain, wind or temperature changes during the day. Having the crew present is not a reason to plant. A delivery that has already arrived is not a reason either.

Handling the trees before they go in

A bare-root walnut tree looks tough, but it is easy to damage. Heat, freezing and drying can damage the roots. You will not see this damage on planting day. It shows up months later as weak trees, or dead trees.

• On arrival: check the count, the labels, the variety and the condition of the roots before anything else. Write down what you received.
• In storage: keep the trees cold, moist, shaded and covered. Cold storage is best.
• In transport to the field: keep the trees covered. A trailer of bare roots in wind and sun for twenty minutes does real damage.
• In the field: take out only as many trees as the crew will plant in the next short period. Keep the rest covered and shaded.
• Do not take more trees out of storage than you can plant in one day.
• If planting stops for weather or a breakdown, put the unplanted trees back into protected storage. Do not stand them at the row end and hope.

If you have no cold store

Most growers do not have one, and this is not a problem. Heel the trees in. Cover the roots temporarily in sand or loose soil, and water the sand or soil enough to keep it moist. Once every three to five days is usually enough. It is best to do this inside a building. Outside also works if the trees are in full shade and never left standing in the sun.

Trees that are heeled in this way keep for several weeks. This is a genuine holding option, not an emergency measure, but every week still uses up a little of the tree’s stored energy (its reserves). Plant on the day the trees arrive if you can.

Preparing each planting site

Finish the ground first. Complete your land shaping, build your berms and let them settle before the trees arrive. A berm is a raised strip of soil built along the row to lift it above wet ground. If you plant first and shape the ground afterwards, your planting depth changes and every tree is at the wrong depth.

Where drainage is only just good enough, plant on berms or mounds. This keeps the crown (the base of the trunk, where the roots begin) above the wettest ground. Chapter 2 covers ploughing, weed clearance and the pre-plant nutrient work, all of which come before planting.

Four ways to dig the hole

Dig the holes before the trees arrive. First mark the tree positions. Chapter 4 covers spacing and layout. Then choose the method that fits your labour and your budget.

An auger is the practical choice for most blocks, and it creates the one defect that this chapter cares most about. Plan the remedy from the start.

Hole size, and how to break the glaze

Dig a hole that fits the roots. Make it deep enough for the roots to sit at their natural depth, and wide enough for them to spread without bending. Do not make it deeper or much wider than that. A hole about 45 to 60 cm wide and 25 to 30 cm deep suits many bare-root walnut trees. But the roots in your hand decide the final size.

Break up glazed hole walls. After augering, move a shovel or a planting tool around the inside of the hole to roughen the surface. This matters most in clay and in damp soil, where the auger leaves a slick wall. Roughen the wall enough to break the smooth surface, but not more than that.

Put nothing in the hole except the soil that came out of it. Do not add fertilizer, manure or compost. Concentrated material against freshly disturbed roots damages them. Also, a hole filled with different soil from the block around it behaves differently from every other hole in the orchard.

The rule above does not contradict chapter 2, which suggests mixing in any phosphorus, potassium and zinc that your soil test calls for before planting. You do that work across the whole field, mixed into the soil, weeks earlier. The rule here is about the hole on planting day.

Depth and root placement

Plant at the same depth the tree grew in the nursery. Look for the nursery soil mark on the trunk. This is the line that the soil reached in the nursery. Put that line at your finished soil level, after the soil has settled.

Keep the graft union (the joint low on the trunk where the variety was grafted) above the final soil line. Check the union after you firm the soil, and check it again after the tree has settled. Checking only before you backfill (put the soil back into the hole) is not enough, because the tree has not finished moving yet.

Spread the roots out in all directions. They should sit naturally. They should not curl up the side of the hole or fold at the bottom. A root forced to bend upward makes a J-shape. This weakens how firmly the tree stands in the ground for the rest of its life.

If the roots do not fit, make the hole bigger. Do not fold them in. Before the tree goes in the hole, cut off broken and dead roots cleanly with a pruning knife. Trim healthy roots only when you really cannot make the hole bigger.

Use a planting board, or a straight bar laid across the hole, to set the depth. Check representative trees against it as you work. Do not wait until the end of the working day, when the row is already backfilled.

Backfill and watering in

Use the soil that came out of the hole. One person holds the tree upright and at the right height. The other person puts the soil back in stages, firming it with hands or feet as they go, so that no air pockets are left.

Leaving no air pockets matters most underneath the roots, where gaps are easy to miss and impossible to fix afterwards. Firm the soil around the roots without compacting the whole root zone (the soil where the roots grow).

Finish with a slight mound where you expect the soil to settle. Keep the nursery mark and the graft union in the right place. Do not leave a permanent hollow around the trunk where water can collect. Water should reach the roots and then move away. It should not sit against the crown. If you are planting in winter, shape the soil so that rain cannot collect at the base of the tree.

Water every tree immediately after backfilling. The purpose of this water is to settle the soil against the roots and to close the remaining air pockets. It is not meant to fill the hole. About 5 to 10 litres per tree is enough. On sandy soil you may need up to 20 litres. Give enough to settle the backfill, then check that water is not standing.

A dormant tree is not photosynthesising, and it is not using water. Watering it fills the air spaces in the soil that its roots need to breathe. Wait until the tree begins to come into leaf, and then until the root zone starts to dry, before you water again. A newly planted tree has a very small root system and uses very little water.

More trees are lost in the first year to constantly wet soil around the crown than to drought. Check the moisture where the roots really are. Make a small auger hole beside a representative tree and look at the soil, or use moisture sensors. Do not judge from the surface, and do not water on a fixed calendar. Chapter 6 covers scheduling once the trees are growing.

Stakes, ties and protection

Stake only where wind, soft new wood or your training system needs it. If your site does not get strong winds, staking is not necessary.

Where you do stake, put the stake on the side the wind comes from, about 20 to 30 cm from the trunk. Then the stake shelters the tree, and the wind blows the tree away from the stake, not against it.

Use a loose, adjustable tie made of soft material, such as cotton or elastic. The tree should be able to move a little, because this movement builds trunk strength. But it should not swing hard or bend over. Keep the tie and the stake away from the graft union and the new shoots.

Protecting the trunk

Protect the trunk against the threats that your block really has.

In hot, dry regions, and anywhere water is short, mulch is worth the effort. Mulch is a layer of material spread on the soil. It cuts evaporation from the soil around a tree that has almost no root system to draw water from. Keep it back from the trunk itself. Mulch piled against the bark holds moisture where you least want it. Chapter 9 covers the orchard floor from the second season onward.

Pruning at planting

With a good finished tree, consider leaving it unheaded rather than automatically cutting it back to a few buds above the graft union. Unheaded means that you do not cut off the top of the tree.

There is experimental support for this. Trials that compared headed and unheaded trees found no long-term height advantage from heading, and the unheaded trees grew as well or better. Unheaded trees also grow more slowly in the first weeks, so they bend less in the wind.

Protect the exposed trunk from sunburn. An unheaded tree carries more bare trunk into its first summer than a headed one does. Paint the trunk, or fit a trunk guard.

Decide your training system before planting day, and write down the cut that you will make. If each crew member decides on each tree, the block has trees with different structures as a result. If you head the trees on planting day, you commit the whole block to a headed, scaffold-based orchard (built around a permanent framework of main branches). Chapter 7 sets out both systems and the full year-by-year work.

Watch: planting, step by step

The video shows the whole job done once, at normal speed, on our own ground. It covers the hole, the roots going in, the backfill, the firming and the first water.

The first weeks

The first few weeks tell you whether your planting operation worked. Check by zone and by crew, not by walking down the middle of the block.

Before the crew leaves each row

• Final depth, and the graft union above the soil line.
• Soil genuinely wet around the roots after watering in.
• Stakes, ties and guards fitted.
• Tree count matching.

Fix problems now, while the soil is still workable and the crew is still standing there.

At the first irrigation

• Emitter output and pressure at row ends and on high ground, not only in the middle. An emitter is the small outlet on a drip line that releases the water.
• The wetted zone (the soil that the irrigation water reaches) under representative trees.
• Anywhere water is standing.

Repair system faults immediately. Set how long each irrigation runs from what you see in the soil, not from your written plan.

Weekly through the first season

• Bud break (the buds opening in spring) and shoot growth.
• Wilting or yellowing leaves.
• Frost or sunburn damage.
• Animal damage, herbicide injury, machinery injury.
• Weeds growing in the wetted zone, where the tree's roots are.

Before you replace a dead tree, find out why it died. Replanting into the same deep, glazed, waterlogged or badly watered position simply repeats the loss. Correct the cause first, then replace. Keep a record of which trees are replacements. Without that record, their smaller size in three years' time can confuse your view of how the block is performing.

Mistakes worth avoiding

• Planting too deep. This is the most common mistake, and it cannot be undone. Use a planting board and check again after watering in.
• Letting roots dry, freeze or overheat. The damage is invisible on the day and shows up as missing trees months later.
• Bending roots to fit the hole. Enlarge the hole instead. A J-rooted tree never anchors properly.
• Planting into wet soil. This smears the hole walls and gives poor soil contact. Wait until the soil is ready.
• Holding the tree up while someone shovels underneath. Loose soil settles and takes the tree down with it. Firm the bottom first.
• Leaving air pockets under the roots. Backfill in stages, firm as you go, then pull on the tree.
• Watering on a fixed schedule. Young roots occupy a tiny volume of soil. No leaf, no water.
• Standing water around the crown. Water to settle the soil, then stop. If water sits, you have a drainage problem, not a watering problem.
• Fertilizer or compost in the planting hole. Feed the field before planting, never the hole.
• Tight ties and forgotten guards. Both girdle trunks. Both are prevented by one inspection round.
• One planting cut applied to every tree without a plan. Decide the training system first.
• Planting because the trees arrived. If the soil is not ready, stop. Store the trees properly and wait.

Before you start

Tell us when you plan to plant, and we will schedule your delivery to match. If you would like someone to look over your plan first (your soil, your irrigation and your timing), send us the details. We will go through the plan with you before we ship the trees.