How far apart should you plant your walnut trees?
Choosing a spacing that fits your variety, your soil, your water and the machines you own.
Spacing decides how many trees you buy, how much your irrigation costs to install, and how hard your orchard is to manage in twenty years.
There is no single correct spacing
The same variety can need different spacing on two different farms. Seven things decide the answer. Some are things that the site does to the tree, and the others are things that you do to it.
What the site does to the tree
- Variety vigour and shape. Vigour is how strongly a tree grows. Some varieties grow upright and compact. Others spread wide. A wide, vigorous variety needs more room.
- Soil depth and fertility. Deep, fertile soil grows bigger trees than shallow or poor soil.
- Water. A tree that has all the water it needs grows more canopy (the branches and leaves of the tree) than a tree under water stress.
- Climate and length of growing season. A long, warm season gives more growth each year than a short one.
What you do to the tree
- How you plan to prune. A traditional, long-lived tree and a mechanically hedged tree (a tree whose sides are cut with a machine) need different spacing from the start.
- Your machinery. Your machines must fit down the row when the trees are mature, not only on planting day. This includes your sprayer, shaker (the machine that shakes the nuts loose), mower and trailer.
- How long you want the orchard to last. A short, intensive planting and an orchard built to last forty years are different designs.
How many trees fit on your land?
| Spacing (row × in-row) | Trees per hectare |
|---|---|
| 10 × 10 m | 100 |
| 8 × 8 m | 156 |
| 8 × 6 m | 208 |
| 7 × 6 m | 238 |
| 7 × 5 m | 286 |
| 6 × 5 m | 333 |
The first number in each row is the row spacing (the distance between rows). The second is the in-row spacing (the distance between trees in the same row). These figures are calculated for a perfect rectangle. In practice, Waltree plans a 7 × 5 m orchard at 280 trees per hectare, not 286. This is because headlands (the strips at the end of the rows where machines turn), roads and access paths take up land in every block. Our yield tables and land calculators also use 280. Expect the same on your own field.
Advantages and disadvantages of wider and closer spacing
More trees per hectare
- More leaf area in the early years, and often an earlier first crop.
- More trees to buy.
- More rows to water, and a bigger irrigation system to install.
- More pruning to manage when the trees meet in the row.
Fewer trees per hectare
- Less to spend at planting.
- Each tree has more room, for longer.
- It takes longer for the orchard to use all its land and light.
Twice the trees does not mean twice the harvest at maturity. When the trees meet in the row, what matters is the light that reaches the productive wood, not how many trunks there are. The productive wood is the wood that carries the nuts. When trees are planted too close together, they shade each other. Dead wood builds up inside the canopy. As a result, you have to prune just to let light back in.
Match the spacing to your variety
Vigour and growth habit (the shape in which the tree grows) differ enough between varieties to move the answer by a couple of metres. Treat the spacings in the table as a starting point, not as a rule.
| Variety | Vigour and habit | What that means for spacing |
|---|---|---|
| Chandler | Moderately vigorous. Spreads sideways rather than up. | A spacing of around 7 × 5 to 8 × 6 m suits it well for a long-lived orchard. A closer spacing is possible, but only if you have a real plan to prune the trees back when they meet in the row. |
| Fernor | Medium vigour, less vigorous than Franquette. | Fernor allows a lot of flexibility. Growers plant it anywhere from wide 10 × 10 m systems to close 8 × 4 m fruiting hedges. A fruiting hedge is a row of trees planted close together and kept as a continuous hedge. It needs regular mechanical pruning to stay productive. |
| Howard | Somewhat less vigorous than Chandler on the same site. | It is a better fit for a closer or hedged system, if that is what you want. |
| Tulare | Grows upright, but is still a vigorous tree. | An upright habit does not mean it needs less room. Check how it performs locally before you plant it close together. |
| Lara | Vigorous. Comes into leaf early. | We have found no reliable spacing trial data for Lara. If you plan to plant a large area of Lara, ask us or your local agricultural advisory service for evidence from a nearby orchard. Do this before you decide the final spacing. |
| Robert Livermore | Moderate vigour. Grown for its red kernel, not for a high yield. | No published spacing guidance exists for it either. As a starting point, treat it like Chandler, and ask for advice before you plant a large block. |
| Franquette (pollenizer: a variety planted among the main variety to supply pollen) | Vigorous, large tree. | Give it more room than your main variety, and place it where its size will not shade productive rows. |
| Fernette (pollenizer) | Moderate vigour. | It fits a spacing similar to Fernor’s. |
Row direction and site layout
Rows that run from north to south usually give the trees the most even light through the day. Start with this direction, but adjust it for the points below.
- Frost drainage. Cold air flows downhill like water on a still night. Never build a road, hedge or bank across the bottom of a slope. It blocks the cold air exactly where you do not want it.
- Slope and erosion. Rows that run straight down a slope can carry rainwater along them and wash the soil away. Plan the row direction together with the drainage.
- Wind. Pollen has to travel between the rows when the trees are in flower. Remember this when you choose the direction.
- Field shape. A perfect north-south grid on a field with an irregular shape can waste a lot of land in the corners. Compare the advantage of better light with the cost of the wasted ground.
- Irrigation. Row length and direction affect the water pressure and the pipe runs (the routes of the pipes). Plan your rows and your irrigation on the same drawing, not one after the other.
Design around your machinery from the start
A spacing that looks fine in your plan can be unworkable when the trunks and canopies are mature.
Leave room to turn and load
Every orchard needs space for:
- machinery to turn at the end of each row
- internal roads
- a place to load the harvest
- access to your pump and filter station.
Find out how much space your equipment really needs to turn safely. Reserve that space before you calculate how many trees you can order.
Plan your pollenizer rows now
Decide where your pollenizer trees go before you stake any row. If you add or move them later, you have to graft into an established orchard. This is slow, and it does not always work well.
The number of pollenizers you need, and how you lay them out, depends on the variety. Each of our variety pages gives our recommended split between the main variety and the pollenizers. If you are unsure, send us your block plan, and we will mark the pollenizer positions for you before you order.
Managing the orchard when the trees meet in the row
Spacing is a decision for the whole life of the orchard, not only the first few years. When the trees meet in the row, you have only three ways to manage them.
| Approach | What it does | What it costs you |
|---|---|---|
| Mechanical hedging | Limits the width of the canopy and gives machines access again. | Hedging removes wood, and the tree has to rebuild it. Chandler can take three to four years to regrow the branching it had, with less crop while it recovers. |
| Structural pruning by hand | Removes crowded, dead and diseased wood while keeping the productive shape of the tree. | It needs skilled labour every year. But it does not slow the tree’s growth the way hedging can. |
| Planned tree removal | Plant extra trees for early yield. Remove some of them when the permanent trees need the room. | This only works if you decide the removal date before you plant, not when the orchard is already crowded. |
Mistakes worth avoiding
Judging the density
- Copying another orchard’s spacing. Their soil, water and machinery may be very different from yours. Judge instead how vigorously trees will grow on your own site.
- Choosing density for early yield alone. A few extra years of early crop can lead to a decade of crowding if you never planned for the mature canopy.
- Assuming that hedging can fix spacing that is too close. Mechanical hedging is regular work that you must keep doing, and it has a real cost. Include it in your plan from the start, or plant the trees further apart.
Laying out the block
- Skipping the machinery test. Do not discover that your equipment does not fit when the trees are mature and have grown together. By then it is too late to change the spacing.
- Forgetting headlands and roads until the end. Reserve that space before you calculate how many trees to order.
- Forgetting where the pollenizers go. Put them on the map before you order trees. Do not wait until you notice a poor nut set (a low share of the flowers developing into nuts).
Before you plant
Nine things to decide
- Your plantable area, after you take out roads, headlands, drains and buildings.
- Your variety, and the vigour that you expect from mature trees on your soil.
- Row spacing × in-row spacing, and the resulting trees per hectare.
- The largest machine you will use, and the distance between rows that it needs when the trees are fully grown.
- Headland width, based on the real turning circle of your equipment.
- Row direction, checked against light, slope, frost drainage and wind.
- Irrigation zones and pipe runs, designed on the same plan as the rows.
- Pollenizer variety and position, marked on the final map.
- Your plan for managing the trees when they meet in the row: hedging, pruning or planned removal.