Which walnut variety should you plant?
Why the answer is usually Chandler — and the three things about your own land that decide whether it is.
For most commercial growers, the answer is Chandler.
That is not a marketing line. It is where the evidence points, and it is where the industry went. Chandler carries nuts along its side shoots, so it starts paying early. Its kernels are the lightest in colour of any major variety, and they come out of the shell in whole halves. It sells both in-shell and as kernel. It suits a modern, mechanised orchard.
The good news is that the decision has fewer moving parts than it looks. You are really answering three questions.
The three questions
- Does my climate suit a late-leafing, late-harvesting variety?
- How many pollenizer trees, and where do they go?
- Can I harvest and dry the crop fast enough to keep the quality I planted for?
Work through those three and the variety decision makes itself.
What you are actually choosing
You are not choosing a name on a nursery order. You are choosing a package of three things that have to fit each other.
The package
What a variety table can tell you, and what it cannot
Nursery sheets and university tables list many numbers for each variety. Some are properties of the variety and will follow the tree to your farm. Others depend far more on your soil and your management, and will not follow. Plant breeders measured this. Here is the useful version.
| What the table says | Can you trust it on your land? |
|---|---|
| Leafing order which variety opens first, second, third | Yes. Almost entirely genetic. The dates will differ in your country; the order will not. |
| Bloom timing relative to other varieties | Yes. You can plan pollenizers from it, then check locally. |
| Shell thickness | Yes. A thin-shelled variety stays thin-shelled. |
| Nut and kernel weight | Mostly. Crop load and water stress still move it. |
| Harvest order | Mostly. The order holds; the calendar date does not. |
| Lateral bearing percentage for example “90%” | Weak. Less than half of this is genetic. It describes trees grown in one place under one management. |
| Shell seal how tightly the shell closes | Weak. Varies a lot with site, season and crop load. Check it in local fruit. |
One practical result: never compare varieties by calendar date from another country. Compare them by the gap between them. If Chandler opens its leaves about two and a half weeks after the earliest varieties in California, it will do something similar in Turkey or Chile — even though the date will be different. Anchor the order to a variety already growing near you.
Chandler, honestly
What it gives you
- Late leafing. Well behind the early varieties, a week or two ahead of the very late ones. That buys three things at once: less spring frost damage, less walnut blight because the young tissue misses the wettest part of spring, and less damage from the first generation of codling moth.
- Side-shoot bearing. About 90% of its lateral buds are capable of fruiting, so you get an early first crop and a shorter wait for your money.
- The kernel. Extra-light in colour — the lightest of the major varieties, and light in hot climates as well as cool ones, which not all varieties manage. About 49% of nut weight (French records give 47–52%), and it comes out in clean halves, which processors pay more for.
- A tree that fits. Moderately vigorous and semi-upright, suited to a trained, pruned, machine-harvested orchard. And it sells both as kernel and in-shell, so you are not tied to one narrow buyer.
Four weaknesses, from its own record
- Young trees are slow to push side shoots. The 90% figure describes buds that can fruit; in the first three or four years the tree may not make many shoots to carry them. Feed and water the young trees properly and this mostly disappears.
- The shell is weak in the first bearing years. Shell strength is only fair early and improves with age. Expect a lower grade-out from your first commercial harvests, and do not judge the orchard by them.
- A little kernel tip shrivel in some years. Driven by crop load, heat and water stress during kernel filling. Water well through July and August and it stays minor.
- It does not always shed pollen through its own bloom. Which is why it needs pollenizers — see below, and note the number is smaller than most growers expect.
On nut size, both of the published figures are true: about 13 g per nut in California, giving a kernel of about 6.5 g, against 9–12 g nuts in French orchards. Nut size depends on where you grow it and how you crop it.
Does your site suit Chandler?
Most sites do. Walnuts are grown commercially from France to Chile to Central Asia. Here are the numbers worth checking before you order trees.
| What to check | Good to go | Fine, with some preparation | Worth advice before planting |
|---|---|---|---|
| Winter minimum | Normal winter lows above −7°C | Lows reaching −7 to −9°C sometimes — keep the soil moist in winter, avoid the frost hollow | Below −9°C in a normal winter |
| Late autumn cold | No sharp cold before the leaves drop | Occasional −2 to −6°C in late autumn | Regular hard cold before dormancy |
| Spring frost | Slope or open ground, cold air drains away | Some frost — Chandler’s late leafing helps a lot | A closed hollow with no way out for cold air |
| Summer heat | Warm summers with irrigation | Above 38°C in midsummer — plan irrigation so the trees never go short | Very hot with no reliable water |
| Autumn rain at harvest | Dry Octobers most years | Some autumn rain — size your harvest and drying equipment for speed | Early, reliable autumn rain every year |
| Spring rain | Dry springs, little blight pressure | Wet springs — budget for more protective treatments and year-round machine access | — |
| Soil | Deep, well-drained, pH 5.5–7.5 | Hard layer, chalk, or wet patches — solve them before planting | Shallow soil over rock, or wet all year |
| Water in July | Peak month covered comfortably | Covered with storage or longer running hours | Cannot cover the peak month |
Two of those deserve a sentence
Autumn rain is the one climate question specific to a late variety. Chandler ripens late. If your autumn rain arrives reliably in early October, harvest gets delayed — and delay is exactly what destroys kernel colour, the trait you chose Chandler for. This does not mean you cannot plant walnuts. It means a slightly earlier variety may serve you better, and it is worth talking through before you order.
Winter cold below −9°C in a normal winter is a real limit. Branch and limb damage starts around −7°C in midwinter, and the risk is worse when the soil is dry.
On water: a grown walnut orchard uses roughly 1,040 mm a year, plus 5 to 30 percent on top for what your irrigation system loses. Chandler is a productive variety, and productive varieties need the water and the nutrition to match. Chapter 6, Irrigation, covers this properly, and chapter 1, Site Selection, covers reading your soil and water reports.
Pollenizers: plant fewer than you think
This is the section most likely to change what you do, so read it carefully.
Why walnuts need pollenizers at all
A walnut tree carries both male and female flowers, but they usually do not open at the same time on the same tree. In most varieties the pollen is shed before the female flowers are ready. Chandler is one of them, and its pollen shed does not always cover its whole female bloom. So you plant a second variety that sheds pollen at the right moment.
- The wind carries walnut pollen. Bees play no part. So placing pollenizers is a wind problem, not an insect problem.
- Walnut pollen dries out and dies quickly. Pollen shed far upwind on a hot dry day will not reach your flowers alive.
Why too much pollen is a problem
Too much pollen makes the female flowers abort. They start to grow, then stop, turn brown and drop, two or three weeks after bloom. Researchers spent ten years looking for a pest, a disease or a nutrient cause. The cause turned out to be the pollen itself.
- Flower loss was highest in the rows next to the pollenizer trees, and fell steadily with distance.
- In one orchard, trees more than 122 m from a pollenizer yielded more than 2.5 times as much as trees within 49 m.
- Where growers removed pollenizer trees from a badly affected variety, yields rose by 20 to 86 percent.
How many, and where they go
Plant 5 percent of your trees as pollenizers, whether your block sits inside an established walnut district or stands alone. Five percent is enough pollen to cover the bloom reliably, without the yield cost that comes from overdoing it. If neighbours already grow walnuts and set good crops, ask them what they do — but ambient pollen in a walnut district is a bonus on top of your own 5 percent, not a reason to plant less.
Where to put them
- Across the prevailing wind, so the pollen blows through the block rather than along one edge.
- About every tenth row, or about 120 m. Pollen concentration starts to fall beyond roughly 50 m from the source, so a much wider interval leaves the middle short — and a much narrower one concentrates pollen where the flower-loss risk is highest.
- In permanent tree positions. If you plan to thin filler trees later, mark the pollenizers so you do not remove them by accident at year ten.
- Where you can harvest them separately. Pollenizers bloom at a different time, so they ripen at a different time. Scattered singly through the block they create a lot-separation problem at harvest; in identifiable rows they do not.
Which pollenizer for Chandler
| Pollenizer | Leafing | What it gives you | What to watch |
|---|---|---|---|
| Franquette our recommendation | Very late | Strong pollen supply and very late leafing, which is useful where spring frost is severe. It is what we supply with a Chandler order, so the whole planting comes from one nursery. | A big, tip-bearing tree that wants 12–15 m of its own. Give it that room and place it where it will not shade productive Chandler rows. It also harvests late, and it is the variety most affected by branch wilt in hot areas. |
| Fernette | Later than Chandler | Produces a lot of pollen, bears on side shoots, and comes into production earlier than Franquette. A smaller tree that sits inside a Chandler block more comfortably. We supply it as Fernor’s pollenizer and can supply it here. | Check bloom and harvest timing in your own conditions before committing a block to it. |
| Cisco | Very late, about a week after Chandler | Similar tree size to Chandler, so no shading problem. Unusually good side-shoot bearing for a late variety, good shell seal, light kernels. It is the name that appears most often in the American records. | We do not produce Cisco, so you would be sourcing it elsewhere. Its own yield is only moderate — it is a pollenizer first. |
What lateral bearing really buys you
Chandler’s side-shoot bearing is one of the main reasons growers choose it, so it is worth being precise about what it does.
The research is direct about this: side-shoot bearing has little influence on the yield of a mature orchard that is well managed. A variety that bears at the tips can reach a similar yield once it fills its space — it just takes longer to get there.
So the value of Chandler’s bearing habit is concentrated in the establishment years: an earlier first crop, a shorter period of spending with no income, a faster payback on your planting investment. That is a real and large financial benefit — but it only appears if you design the orchard to collect it.
- Small differences in the percentage mean nothing. A variety listed at 90% is not reliably earlier-bearing than one at 70%. Do not rank varieties on this number.
- Planting density is part of the variety decision. If early production is the benefit, you need enough trees early to capture it. Chapter 4, Orchard Design and Tree Spacing, owns that decision and gives the spacings we recommend.
One more link between the two. Chandler needs light inside the canopy. Its fruiting positions are spread along the shoots, not just at the illuminated tips, so shading costs it more than it costs a tip-bearing variety. And the flower buds for next year form in June and July of this year — so the light you allow into the canopy this summer sets your flower number for next summer. Maintenance pruning is not optional on a lateral-bearing variety.
Harvest and drying decide how much quality you keep
This is the part of the variety decision that growers most often treat as a separate subject. It is not separate. Chandler’s kernel colour is the reason to plant Chandler, and colour is lost in the field, in hours.
Most of the colour loss happens in the first nine hours after the nuts hit the ground. Above 32°C, nuts in the sun lose colour fast; in the shade the same happens above 38°C. Nuts still in their hulls heat up faster still, because the hull holds the heat in. And nuts left on damp ground pick up mould and shell stain — a stained shell cannot be sold in-shell.
When to harvest
Forget the calendar. The kernel is at its lightest colour when the packing tissue between the two kernel halves has just turned from white to brown.
The problem is that the hull is often not ready yet. In cool, humid climates the kernel and the hull mature almost together, a few days apart. In hot, dry climates the kernel can be ready up to three weeks before the hull opens — and all that time, quality is falling.
An economic harvest is when about 80 percent of the nuts can be shaken off and 95 percent of them can be hulled. In hot interior climates that is two to three weeks after the kernel is mature, with a second shake about a week later for the rest. So the gap between “kernel ready” and “hull ready” on your site is what decides how much of Chandler’s colour advantage you actually sell. Humid nights and light autumn rain close the gap quickly. Hot dry autumns open it wide.
Drying and storage
Drying
- Dry to 8 percent moisture.
- Never let the drying air go above 43°C. Above that the oil turns rancid and the kernels become inedible — and the damage does not show at once. It appears weeks or months later, in storage, at the buyer’s warehouse.
- Drying takes less time later in the season, because nuts left on the tree after the hull opens dry naturally.
Storage
- Walnut is the nut most prone to going rancid, because of its oil composition. There is no variety you can choose to avoid this — breeders have looked and found none.
- What does work is storage. Cold storage at 1–2°C with reduced oxygen has kept kernels sound for as long as two years.
- Watch the pellicle, the thin brown skin on the kernel. It is the kernel’s natural protection, and when it darkens in storage the shelf life is already shortening.
Size the chain before you size the block
Work out the peak tonnes per day that must move from tree to dryer on your hottest likely harvest day. Then check your shaker, sweeper, pickup, huller and dryer against that number. If the chain cannot keep up, plant a smaller Chandler block and spread the rest of the harvest with a second variety — or with your pollenizers, which ripen at a different time anyway.
A modest spread of harvest dates keeps your dryer working steadily. Too many varieties, though, makes pollination, spraying, harvest, drying, lot separation and marketing all harder. Keep Chandler as the main variety and add others only when they earn their place.
Disease: what the variety choice can and cannot do
Disease risk is a conversation between the variety and your site. The same variety carries different risk in a wet spring climate and a dry one.
Walnut blight
What variety choice gives you is avoidance, not resistance. Chandler’s late leafing means its young tissue misses much of the wettest part of spring, and Californian records describe only moderate blight problems in most districts for exactly that reason. French records, from a wetter spring climate, describe Chandler as sensitive. Both are correct. Your own spring rainfall record decides which description applies to you.
- Infection needs free water on the tissue. Leaf wetness duration matters more than total rainfall.
- The bacteria overwinter inside next season’s buds and catkins, so they are already in the canopy when growth starts. Clean-up alone will not remove them.
Budget for the treatments. In dry spring areas growers commonly need only one to three protective treatments a year. In wet spring areas three to six or more is normal. That difference roughly doubles a recurring annual cost for the life of the orchard, so it belongs in your planting budget. Ask your local adviser what is registered where you are — this differs in every country.
Also make sure you can get a machine into the orchard in a wet spring. A grass or strip orchard floor gives you footing when the ground is soft and you need to treat. On a frost-marginal site the opposite argument applies — bare, cultivated soil warms and re-radiates better on a frost night. Choose according to which risk is larger on your land.
The others worth knowing
| Disease | What it means for your variety choice |
|---|---|
| Anthracnose | French records list Chandler as sensitive. Our main source, from California, does not cover this disease at all. If you are in Europe, Turkey or another humid-summer region, treat anthracnose as a real question and get local advice on it. |
| Trunk cankers | Deep bark canker is mainly a Hartley problem, not a Chandler one. But it enters through deep wounds, and mechanical harvesters make deep wounds. A harvester injury stays open to infection for about ten days, and dirty shaker pads carry the bacteria from tree to tree. Keep shaker pads clean and in good condition. |
| Blackline | A virus carried in walnut pollen. Once inside an English walnut tree it moves slowly downward, and when it reaches the graft union the tissue there dies — a black line forms, the ring widens, and eventually the top of the tree dies. If it is present in your district, the strategy is not a resistant variety: it is to build an orchard that pays for itself early. Plant at good density with a precocious, side-shoot-bearing variety, so the orchard has earned its establishment cost well before decline starts. That is an argument for Chandler on a blackline site, not against it. When replanting into infected ground, look at a pollination chart — a later-blooming variety can miss the pollen shed of infected neighbours, because the virus only spreads during the short pollen-shedding window. |
| Codling moth | Early-leafing varieties meet the first spring generation head on. Late-leafing varieties, Chandler among them, largely miss it. That is a recurring annual saving. |
| Hull behaviour | A real variety difference that rarely appears in catalogues. Some varieties’ hulls open wide and expose the nut before harvest; others just loosen their grip. Exposed nuts are more attractive to boring insects, but less prone to mould because the wet hull comes away. Ask which behaviour your candidate shows locally, and match it to whichever risk is larger on your site. |
When a different variety makes sense
Chandler should normally be the main variety. Other varieties belong in the plan when they have a defined job. Where something listed here is not one we produce, the table says so.
| The job | Varieties to consider | What to know |
|---|---|---|
| Pollenizer for Chandler | Franquette, Fernette | See the pollenizer table above. Franquette is our recommendation and wants 12–15 m of its own; Fernette is the smaller alternative. |
| Severe spring frost | Franquette, Fernor and other very late varieties | Later leafing avoids more frost, but the harvest is later and the trees are usually bigger. Fernor is a variety we grow and recommend for high-altitude and frost-prone sites. |
| Spreading harvest across your equipment | Tulare and other mid-season varieties | Tulare is the strongest of this group — good side-shoot bearing, light kernels, 53% kernel — and we grow it. Earlier varieties trade harvest convenience for more blight and codling moth exposure. |
| Very large in-shell nuts | Howard | A variety we grow. Beware the general rule that big nuts come with conditions: several of the very-large-nut varieties leaf early, which is a poor trade where late frost and spring rain are likely. |
| An in-shell contract with a traditional buyer | Hartley | Not a variety we produce. Long the classic in-shell variety, with good colour — but it bears at the tips, comes into production slowly, needs 9–12 m spacing, and is by far the most exposed variety to deep bark canker. It wants deep, fertile, well-drained soil and good irrigation. |
| Local adaptation | Regionally trialled Turkish, Balkan, Italian, Spanish or French material | Where local trial data exist for your climate, they matter more than any figure in this chapter. Use them. |
Two cautionary examples
Neither of these is a candidate. They are here because each one teaches something about how to read a variety table.
- Serr looks excellent on paper — a large nut, 57% kernel, strong demand. It is defeated by flower abortion, sometimes losing more than 90 percent of its female flowers. Serr should be planted with no pollenizers at all.
- Chico has the highest side-shoot bearing figure of any variety, at 96 percent. Processors lost interest in it anyway: the nut is small, the kernel is hard to remove whole, only 60 percent of kernels are light, and its early bloom makes it very exposed to blight and codling moth.
Mistakes worth avoiding
Reading the numbers
- Reading the lateral-bearing percentage as a mature yield forecast. It buys precocity. Design your density plan to collect that, and do not rank varieties by the number.
- Copying a calendar date from another country. Copy the interval between varieties instead, anchored to something growing near you.
- Choosing a thin shell or a high kernel percentage without asking your buyer. Get the specification in writing before you plant.
Planning the block
- Planting 10 percent pollenizers because that is the traditional number. Five percent.
- Buying pollen to improve set. Never.
- Assuming late leafing fixes a frost hollow. It helps a great deal. It does not turn a closed hollow into good ground. Use both the right place and the right variety.
- Planting more of one variety than your dryer can handle. Size the chain first, then the block.
Before you order trees
What to have in front of you
- Your winter minimum temperatures and your late-frost record.
- Your autumn rainfall pattern for the weeks around harvest.
- Your spring rainfall and leaf-wetness pattern, and a realistic budget for protective treatments.
- A soil report by depth and a water report, read together, and your July water figure.
- Whether blackline, crown gall, oak root fungus or nematodes are present in your district.
- Your pollenizer variety, the percentage (5%), and a map showing wind direction, rows and permanent tree positions.
- Your planting density and your irrigation design.
- Your buyer’s written specification: kernel colour class, halves, size, moisture, in-shell or kernel, delivery date.
- The peak tonnes per day your harvest and drying equipment can actually handle.
The short version
Plant Chandler, unless something specific on your land argues otherwise. It gives you early production, the lightest kernels on the market, clean halves, and buyers in both the kernel and in-shell trades.
Plant fewer pollenizers than the old advice says — 5 percent, across the wind, about every tenth row, in permanent positions you will not thin out by mistake.
Size your harvest and drying equipment before you size the block. Chandler’s kernel colour is worth money only if it reaches the dryer in the first hours after it hits the ground, and leaves the dryer having never seen air above 43°C.