Vegetable Garden Fertilizer Chart for Canada — NPK Needs by Crop
A free vegetable garden fertilizer chart for Canadian gardeners — NPK decoded, crop-by-crop needs (heavy/medium/light feeders), organic vs synthetic compared, and a season-long application schedule.
A vegetable garden fertilizer chart matters because different crops have radically different needs — and treating them the same is why most Canadian gardens underperform. Too much nitrogen turns tomato plants into leafy bushes with no fruit. Too little in heavy-feeding corn or brassicas means stunted plants that never catch up in a 120-day growing season. And applying fertilizer to beans or peas at all can actively hurt them.
This guide cuts through the confusion — what NPK actually means, which crops need what (the full chart is below), when to apply, and whether organic or synthetic makes more sense for your garden.
Vegetable garden fertilizer chart at a glance: Use balanced 10-10-10 at planting. Switch to 5-10-5 at transplant time for root support. Move to 5-10-10 once tomatoes and peppers begin flowering. Beans and peas need no nitrogen — they fix their own. Heavy feeders (tomatoes, corn, brassicas) need 2–3 applications per season; light feeders (beans, herbs) need none.
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🌱 Free Fertilizer CalculatorWhat NPK Actually Means
Every fertilizer bag sold in Canada shows three numbers — for example 10-10-10 or 20-10-10. These are the NPK ratio: the percentage by weight of nitrogen (N), phosphorus (P), and potassium (K). A 10 kg bag of 10-10-10 contains 1 kg each of nitrogen, phosphorus, and potassium.
Sources: N-P-K nutrient roles — basic plant nutrition; consistent with this site’s fertilizer chart by crop and fertilizer calculator.
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Nitrogen — Leaf & stem growth
Drives green, leafy growth. Essential for spinach, lettuce, kale, and corn. Too much nitrogen on fruiting crops (tomatoes, peppers) causes lush leaves with few flowers and fruit. Deficiency shows as yellowing of older leaves first.
Phosphorus — Roots & flowers
Supports root development, flowering, and fruit set. Most critical at planting and during flowering. Deficiency shows as purple or reddish tinge on leaves and stems, especially in cold Canadian spring soil when phosphorus uptake slows.
Potassium — Strength & disease resistance
Improves overall plant health, water uptake efficiency, disease resistance, and fruit quality. Important for root vegetables — potatoes, carrots, and beets store better with adequate potassium. Deficiency shows as brown, scorched leaf edges.
Vegetable Garden Fertilizer Chart — Needs by Crop
The single most important thing to understand about fertilizing vegetables is that different crops have very different needs. Treating everything the same is why gardens underperform.
| Crop | Feeder type | At planting | Follow-up feeding | Notes |
|---|---|---|---|---|
| Tomatoes | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | Add bone meal to the planting hole to support root establishment |
| Peppers | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | Add bone meal to the planting hole to support root establishment |
| Corn | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Squash | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Cucumbers | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Eggplant | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Cabbage | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Broccoli | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Brussels sprouts | Heavy | 5-10-5 or 10-10-10 worked into soil | Side-dress balanced fertilizer 3-4 weeks after transplanting; switch to low-nitrogen 5-10-10 once flowering begins | High-output producer; exhausts soil nutrients quickly |
| Lettuce | Medium | One application of balanced fertilizer at planting | Optional second light nitrogen feed mid-season if growth slows | Leafy green |
| Spinach | Medium | One application of balanced fertilizer at planting | Optional second light nitrogen feed mid-season if growth slows | Leafy green |
| Kale | Medium | One application of balanced fertilizer at planting | Optional second light nitrogen feed mid-season if growth slows | Leafy green |
| Beets | Medium | One application of balanced fertilizer at planting | Adequate potassium for storage quality; reduce nitrogen in the final 4 weeks before harvest | Excess late nitrogen causes forking in carrots and poor storage in beets |
| Carrots | Medium | One application of balanced fertilizer at planting | Adequate potassium for storage quality; reduce nitrogen in the final 4 weeks before harvest | Excess late nitrogen causes forking in carrots and poor storage in beets |
| Onions | Medium | One application of balanced fertilizer at planting | Adequate potassium for storage quality; reduce nitrogen in the final 4 weeks before harvest | Excess late nitrogen causes forking in carrots and poor storage in beets |
| Garlic | Medium | One application of balanced fertilizer at planting | Adequate potassium for storage quality; reduce nitrogen in the final 4 weeks before harvest | Excess late nitrogen causes forking in carrots and poor storage in beets |
| Potatoes | Medium | One application of balanced fertilizer at planting | Adequate potassium for storage quality; reduce nitrogen in the final 4 weeks before harvest | Excess late nitrogen causes forking in carrots and poor storage in beets |
| Beans | Light | Little or none; single phosphorus application (bone meal) at planting | None | Fixes its own nitrogen via root bacteria; added nitrogen reduces pod production |
| Peas | Light | Little or none; single phosphorus application (bone meal) at planting | None | Fixes its own nitrogen via root bacteria; added nitrogen reduces pod production |
| Radishes | Light | Little or none; single phosphorus application (bone meal) at planting | None | Fast crop; lean soil is sufficient |
| Basil | Light | Little or none; single phosphorus application (bone meal) at planting | None | Herbs prefer lean conditions and produce more aromatic oils in less fertile soil |
| Parsley | Light | Little or none; single phosphorus application (bone meal) at planting | None | Herbs prefer lean conditions and produce more aromatic oils in less fertile soil |
| Thyme | Light | Little or none; single phosphorus application (bone meal) at planting | None | Herbs prefer lean conditions and produce more aromatic oils in less fertile soil |
| Oregano | Light | Little or none; single phosphorus application (bone meal) at planting | None | Herbs prefer lean conditions and produce more aromatic oils in less fertile soil |
🔴 Heavy Feeders — Need Regular Fertilizing
Crops: Tomatoes, peppers, corn, squash, cucumbers, eggplant, cabbage, broccoli, Brussels sprouts
These crops are high-output producers that exhaust soil nutrients quickly. In Canada's short season they need to establish, grow, flower, and fruit all within 4–5 months — consistent nutrition is critical.
Work 5-10-5 or balanced 10-10-10 into soil. Add bone meal to planting hole for tomatoes and peppers to support root establishment.
Side-dress with balanced fertilizer once plants show active new growth. This is the key feeding for the whole season.
Switch to a low-nitrogen tomato fertilizer or plant food (5-10-10) for tomatoes and peppers. High nitrogen now causes foliage at the expense of fruit set.
🟡 Medium Feeders — One or Two Applications
Crops: Lettuce, spinach, kale, beets, carrots, onions, garlic, potatoes
One fertilizer application at planting is usually sufficient for most medium feeders. Leafy greens benefit from a second light nitrogen feed mid-season if growth slows. Root vegetables need adequate potassium for good storage quality — reduce nitrogen in the final 4 weeks before harvest to avoid forking in carrots and poor storage in beets.
🟢 Light Feeders — Fertilize Sparingly or Not At All
Crops: Beans, peas, radishes, herbs (basil, parsley, thyme, oregano)
Beans and peas fix their own nitrogen from the air via root bacteria — adding nitrogen fertilizer pushes leafy growth and reduces pod production. A single phosphorus application at planting (bone meal) supports root establishment. Herbs generally prefer lean conditions and produce more aromatic oils in less fertile soil. Over-fertilized basil grows fast but loses flavour.
Organic vs Synthetic Fertilizer in Canada
Both work. The right choice depends on your goals, budget, and how much time you want to spend:
| Synthetic | Organic | |
|---|---|---|
| Speed | Days | Weeks |
| Precision | High — exact ratios | Lower — variable |
| Burn risk | High if over-applied | Low |
| Soil improvement | None | Significant over time |
| Cost per season | $ Low | $$ Medium–High |
| Best for | Quick fixes, heavy feeders | Long-term soil health |
Best Organic Fertilizers for Canadian Vegetable Gardens
Fast-acting nitrogen boost. Dilute in water and apply every 2–3 weeks for heavy feeders. Smells strong but breaks down quickly. Available at most Canadian garden centres.
Leafy crops, mid-season boost
High phosphorus for root development and flowering. Work into planting holes at transplant time. Slow release over the season. Especially useful for tomatoes, peppers, and root vegetables.
At planting, root crops
Very high nitrogen, fast-acting. Use sparingly for nitrogen-deficient leafy crops. Easy to over-apply — use half the recommended rate and increase if needed. Also deters some animal pests.
Nitrogen deficiency only
Gentle, balanced, impossible to over-apply. Excellent for seedlings and transplants. Mix into potting soil or use as a top dressing. Low nutrient numbers mean you need to use larger volumes for visible results.
Seedlings, containers
Low nutrient numbers but improves soil structure, water retention, and microbial activity — which unlocks nutrients already in your soil. The foundation of any good fertility program. See our composting guide to make your own for free.
Soil building, all crops
If you would rather buy one balanced organic feed than mix bone meal, blood meal, kelp and rock dust yourself, this is the Canadian-made blend most home gardeners reach for — a gentle, slow-release 4-4-4 that feeds soil life instead of forcing growth. Work it into beds at planting and side-dress heavy feeders mid-season.
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Fertilizer Schedule for Canadian Vegetable Gardens
Timing fertilizer correctly through Canada's growing season makes a bigger difference than which product you use:
🌱 Pre-season — April to early May
Work 5–8 cm of compost into beds 2–3 weeks before planting. This is the single most impactful fertility step for the whole season. For soil that hasn't been amended in 2+ years, add a balanced granular fertilizer at half the recommended rate alongside the compost.
🌿 At transplanting — May to early June
Add bone meal to each planting hole for tomatoes, peppers, squash, and cucumbers. Water transplants with diluted fish emulsion or a weak balanced fertilizer solution at planting (half strength) to reduce transplant shock and encourage root establishment.
☀️ Active growth — June to July
Side-dress heavy feeders (tomatoes, corn, brassicas) with balanced granular fertilizer 3–4 weeks after transplanting. Scratch lightly into the soil surface 15 cm from the stem and water in well. This is the main mid-season feeding that powers the bulk of growth and fruit set.
🍅 Fruiting — July to August
Switch tomatoes and peppers to a low-nitrogen formula (5-10-10 or tomato-specific fertilizer) once flowering begins. Continue every 3–4 weeks through the fruiting period. Stop fertilizing root vegetables 4 weeks before anticipated harvest. Do not fertilize during heat waves — stressed plants can't absorb nutrients and fertilizer salts can burn roots.
🍂 End of season — September to October
Stop all fertilizing once plants start winding down. After clearing beds, add a layer of compost and leave it on the surface over winter — earthworms and freeze-thaw cycles will work it in by spring. This is the most efficient way to build fertility over the long term.
Application Tips for Canadian Gardens
Always water in fertilizer
Apply granular fertilizer to moist soil and water thoroughly immediately after. Fertilizer applied to dry soil can burn roots. Never apply during drought stress — water first, wait 24 hours, then fertilize.
Keep away from stems
Apply granular fertilizer at least 10–15 cm from plant stems, scratched in lightly. Direct contact with stems causes fertilizer burn. The feeder roots that actually absorb nutrients extend out to the drip line of the plant — fertilize there.
Less is more
Over-fertilizing is more common and more damaging than under-fertilizing. Start with half the recommended rate if you're unsure about your soil's existing fertility. You can always add more — you can't undo a fertilizer burn.
Test your soil
A soil test every 2–3 years ($20–$40 through provincial agricultural labs or garden centres) tells you exactly what's missing. Without a test you're guessing. Most Canadian gardens are low in phosphorus and have reasonable potassium — but it varies widely by region and history.
💡 Canadian tip: Phosphorus becomes nearly unavailable to plants when soil temperature is below 10°C — common in Canadian springs until late May. Even if your soil has good phosphorus levels, plants can show deficiency symptoms in cold spring soil. This is normal and resolves as soil warms. Avoid over-applying phosphorus in response to purple-tinged spring leaves.
Work Out What the Soil Already Has
The chart above gives a starting ratio for each crop. What it cannot tell you is what is already in your ground — and that is the half of the equation that decides whether 10-10-10 is the right bag, a waste of money, or actively the wrong thing. A bed that has had compost worked in every spring for five years is a completely different starting point from a new build over subsoil, and no chart can see the difference.
Most Canadian gardens come back low in phosphorus with reasonable potassium — but that is a tendency, not a reading. It varies widely by region and by what the bed has been fed before. A test is what turns the chart above from a guess into a decision.
What a home kit can and cannot tell you
- A lab is the accurate option. Provincial and university soil labs run a proper analysis for roughly $20–$40 and report far more than four numbers. If you are amending a whole garden, or something has been going wrong for several seasons, send a sample away.
- A capsule kit is directional — which is still worth having. It is enough to tell you whether phosphorus is genuinely low before you spend on a bag of 5-10-10, and you get the answer the same day instead of in three weeks.
- The four readings are not equally trustworthy. pH and potassium are the dependable ones. Nitrogen is the least reliable of the four — nitrogen moves through soil quickly, and a colour match catches one moment of it. Treat a nitrogen result as a hint and the pH as a fact.
- Read the test count properly. The capsules are split across four nutrients, so “20 tests” means five each of pH, N, P and K — not twenty goes at the same question. Testing one bed on all four uses four capsules.
- Give the colour hours, not minutes. It can take several hours to develop fully. Reading it early is the commonest way to get a wrong answer out of a kit that is working perfectly.
- The capsules are fiddly to open. Small scissors beat fingernails, and save you spilling one of the five you have.
- They degrade in about a year. Buy in the season you actually plan to test in, rather than stocking up ahead.
The two kits below are the same test — they differ only in how many capsules come in the box. So the question is not which is better, it is how much testing you are honestly going to do: one plot once, or several beds now and the same beds again next spring to see whether what you did worked.
Twenty capsules — five each of pH, nitrogen, phosphorus and potassium. Enough to test one garden properly across all four, with a spare go at any reading you doubt. This is the one to pick if you are checking a single plot, once, before buying fertilizer for it.
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The same test with double the capsules — ten each of pH, nitrogen, phosphorus and potassium. Worth the step up if you have several beds with different histories, or if you intend to re-test next spring and find out whether the amendment actually moved anything. Capsules keep about a year, so buy it for a season you will use it in.
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One thing a capsule kit is not: the probe-style meters sold for moisture and pH are a different instrument and do not measure N, P or K at all. If the question is which NPK to buy, it is the chemical test you want.
Can You Still Buy Phosphorus Fertilizer in Canada?
Yes — for a vegetable garden, everywhere in the country. This comes up because the chart above asks for 5-10-5, 10-10-10 and 5-10-10, and anyone who has walked a Canadian garden-centre aisle lately has noticed that most of the lawn bags now read 30-0-3 or 10-0-20, with a zero in the middle. That is a real restriction, but it is a lawn restriction.
Phosphorus running off turf into lakes and rivers feeds algal blooms, so several provinces limit what can be applied to residential lawns. Vegetable gardens, fruit trees and ornamental beds are generally exempt — the rules target the surface that produces most of the runoff. Practically: the P-free bags are in the lawn aisle, and 10-10-10, 5-10-10 and bone meal are still on the shelf in the garden aisle.
- Ontario: Provincewide lawn P restriction unless a soil test shows deficiency. Stricter rules in the Lake Simcoe watershed.
- Quebec: Provincewide ban on P-containing lawn fertilizer except for establishing a new lawn.
- Manitoba: Lake Winnipeg watershed P restrictions.
- New Brunswick: Provincewide P restrictions on residential lawns.
- Nova Scotia: P restrictions on residential lawn applications.
- BC, Alberta, Saskatchewan, PEI, Newfoundland and the territories: No provincewide P lawn restriction as of 2026, but municipalities may have their own bylaws — especially around vulnerable watersheds.
- Vegetable gardens, ornamentals, fruit trees: Generally exempt across all provinces. Every ratio in the chart above is legal to buy and apply on a food garden.
One practical consequence for the chart: if the only fertilizer in the shed is a P-free lawn blend, it is the wrong bag for the vegetable bed. Fruiting crops and transplants want that middle number, which is exactly what the lawn product has had removed.
Reading the Plant — Nutrient Deficiency Signs
Before you reach for a bag, let the plant tell you what it's short on. Most deficiencies show a recognizable pattern — and where on the plant the symptom appears (old lower leaves vs new top growth) is the biggest clue, because mobile nutrients (N, P, K, Mg) get pulled from old leaves to feed new ones, while immobile ones (Ca, Fe) show up first in new growth.
| Nutrient | What you see | Where | Fix |
|---|---|---|---|
| Nitrogen (N) | Uniform pale-green to yellow, whole leaf; stunted, spindly growth | Oldest (lower) leaves first | Fast: fish emulsion or blood meal / a higher-N feed. See the chart above. |
| Phosphorus (P) | Dull green with purple/red tinge on leaves and stems | Older leaves | Often just cold soil (<10°C) — wait for warmth before adding P. Bone meal if a real deficiency. |
| Potassium (K) | Yellowing then browning/scorch along leaf edges and tips | Older leaves | Kelp meal, wood ash (sparingly), or a higher-K feed. |
| Magnesium (Mg) | Yellowing between the veins; veins stay green | Older leaves | Epsom salts (1 tbsp/4 L) as a foliar spray or soil drench. |
| Calcium (Ca) | Distorted/dying new growth; blossom-end rot on tomatoes & peppers | New (top) growth | Usually inconsistent watering, not low calcium — water evenly, mulch. Lime only if a soil test confirms low Ca. |
One caution: yellowing from overwatering or root problems looks a lot like nitrogen deficiency. If the soil is soggy, fix drainage first — feeding a waterlogged plant won't help. When symptoms are widespread or you're unsure, a soil test (above) beats guessing.
Frequently Asked Questions
What fertilizer numbers should I use for vegetables?
A balanced 10-10-10 works for most vegetables at planting. Use higher phosphorus (5-10-5) at transplant time, and switch to lower nitrogen (5-10-10) for tomatoes and peppers once they begin flowering. Use the fertilizer calculator for exact application rates.
Do beans and peas need fertilizer?
No — beans and peas fix their own nitrogen. Adding nitrogen fertilizer reduces pod production. A small amount of bone meal at planting for phosphorus is sufficient.
Can I use compost instead of fertilizer?
Yes — annual compost applications build long-term fertility and are sufficient for many gardens. Heavy feeders like tomatoes and corn may still benefit from supplemental fertilizer even with good compost, especially in a short Canadian season. See our composting guide.
Why are my tomato leaves purple in spring?
Purple leaves on tomatoes in spring almost always indicate phosphorus deficiency caused by cold soil — not a lack of phosphorus. Phosphorus becomes unavailable below 10°C, common in Canadian May soil. Wait for soil to warm and it resolves on its own. Don't over-apply phosphorus in response.
Is phosphorus fertilizer banned in Canada?
Not banned — restricted on lawns in Ontario, Quebec, Manitoba, New Brunswick and Nova Scotia. Vegetable gardens are generally exempt, so every ratio in the chart above is legal to buy nationwide. That is why the lawn bags read 30-0-3 and the garden bags still read 10-10-10 — and why a leftover lawn blend is the wrong thing to put on a tomato bed.
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