What is the 30-plants-per-week challenge?
The 30-plants-per-week target comes from the American Gut Project, the largest open-source citizen-science microbiome study to date, co-led by Tim Spector at King's College London and Rob Knight at UC San Diego. Among more than 11,000 participants, the team found that people eating at least 30 distinct plant types per week had measurably more diverse gut bacteria than those eating ten or fewer. The diversity gap held even after controlling for vegetarian status, antibiotic use, and country.
Why diversity matters: different gut microbes feed on different plant fibres and polyphenols. A diet that's mostly chicken-and-rice keeps a narrow subset of microbes well-fed; a diet that drifts across vegetables, fruits, whole grains, legumes, nuts, seeds, herbs, and spices feeds a wider community. Wider communities are more resilient to disturbance — antibiotics, illness, travel — and produce a broader range of short-chain fatty acids, the metabolic by-products that line and protect the gut.
Spector has spent the last decade popularizing the number through books (Spoon-Fed, Food for Life), the ZOE personalised-nutrition study, and a community of practitioners and home cooks who count plants weekly. The challenge is deliberately simple: 30 different plants, any quantity, any preparation, every week. This tracker is one way to keep score without spreadsheets or signups.
How it works
- Pick your target and week start. 30 is the default — the figure from the American Gut Project. Drop it to 20 or 25 for the first few weeks if you'd rather build the habit before chasing the round number. Week starts Monday by default; switch to Sunday in settings if that matches your shopping pattern.
- Tap each plant as you eat it. The library has about 120 entries across six categories — vegetables, fruits, whole grains, legumes, nuts and seeds, herbs and spices. Search or browse by category. Tapping toggles a plant on; tapping again removes it. The ring fills as you go.
- Watch the category breakdown. The six small tiles under the ring show how many plants you've logged in each category. If one tile is empty, that's the cheap win for the week — a single chickpea bowl or a single seeded snack moves the whole picture.
- Round out with herbs and spices. Herbs and spices score a quarter-point each (the Spector convention), so 12 of them gives you 3 points — not 12. That's intentional: a sprinkle of oregano isn't doing the same fibre work as a lentil. They're how you take a 27-point week to a 30-point week with one well-seasoned meal.
- Streak — every completed week at target. Each week you hit the target adds one to your current streak. The current week only joins the streak at the end of the week. Milestones unlock at 4 weeks ("Month"), 13 weeks ("Quarter"), and 52 weeks ("Year").
- Edit past weeks from the history strip. The 12-week history bar shows each completed week's score. Tap any past week to open its log and add the bean stew you forgot to record on Wednesday. The current week is the one marked with the outline.
What counts as a plant?
The library covers six categories. Each plant counts once per week, regardless of how many times you ate it — an apple Monday and an apple Thursday is one apple, not two.
Vegetables
Artichoke, arugula, asparagus, beet, bell pepper, bok choy, broccoli, brussels sprouts, cabbage, carrot, cauliflower, celery, cucumber, eggplant, fennel, garlic, green bean, kale, leek, lettuce, mushroom (a fungus, but Spector includes it), okra, onion, parsnip, potato, pumpkin, radish, spinach, sweet potato, swiss chard, tomato, turnip, watercress, zucchini.
Fruits
Apple, apricot, avocado, banana, blackberry, blueberry, cantaloupe, cherry, coconut, cranberry, date, fig, grape, grapefruit, kiwi, lemon, lime, mango, olive, orange, papaya, peach, pear, persimmon, pineapple, plum, pomegranate, raspberry, strawberry, watermelon.
Whole grains
Amaranth, barley, brown rice, buckwheat, bulgur, corn, farro, millet, oats, quinoa, rye, sorghum, spelt, wild rice. White flour and refined grains don't count — the relevant fibre is in the bran and germ.
Legumes
Black bean, black-eyed pea, chickpea, edamame, fava bean, green pea, kidney bean, lentil, lima bean, mung bean, navy bean, peanut (a legume, not a nut), pinto bean, soybean, split pea.
Nuts and seeds
Almond, brazil nut, cashew, chia seed, flax seed, hazelnut, hemp seed, macadamia, pecan, pine nut, pistachio, poppy seed, pumpkin seed, sesame seed, sunflower seed, walnut.
Herbs and spices
Basil, bay leaf, black pepper, cardamom, chili, chive, cilantro, cinnamon, clove, coriander, cumin, dill, fennel seed, ginger, mint, mustard seed, nutmeg, oregano, paprika, parsley, rosemary, saffron, sage, tarragon, thyme, turmeric.
Why a tracker beats a spreadsheet
The 30-plants challenge has a quirk: it's easy in principle and slippery in practice. You'll eat 20 different plants without trying and assume you hit 30; you'll eat the same 12 plants in three meals and assume that was a variety day. The only way to know is to keep a running list, and the only way a running list survives the week is if logging takes one tap.
This tracker exists to make logging cheap. A 120-plant library covers most everyday ingredients in two screens. The search box jumps to the chip in a few keystrokes. Already-added plants visibly check off so you don't accidentally try to add them twice. The herbs-and-spices quarter-weight is built into the score so you don't have to do the arithmetic. Custom-plant entries (jicama, samphire, longan, taro) save back to the library so unusual ingredients only have to be typed once.
Tips for hitting 30
- Treat the herbs and spices category as the variety reservoir. A simple weekly habit of "shake three jars on each savoury dish" — say, paprika + cumin + black pepper — adds five points to the herb total over the week. Even at a quarter-weight, that's slack you can lean on when the rest of the week was tight.
- Stock-cook a legume on Sunday. A pot of chickpeas, a pot of black beans, a pot of lentils — any one of those gives you a category check that lasts five days. Most people score zero on legumes in a typical week without realising it.
- Buy three colors of berries, not three pints of one. A strawberry punnet is one plant whether it lasts you one day or four. Splitting the same money across strawberries, blueberries, and raspberries gives you three plants instead of one.
- Snack on seeds and nuts in a small bowl. A jar mix of pumpkin, sunflower, and sesame seeds plus almonds and walnuts is five plants — and the mix takes the same shelf space and prep time as a single bag of cashews.
- Don't try to hit 30 in the first week. The streak is the long game. Many people land somewhere around 18–22 their first week, 25–28 their second, and 30+ from week three onwards once they've noticed the cheap-win categories. Setting the target to 25 for two weeks and then bumping it is a perfectly reasonable approach.
What the tracker won't tell you
This is a variety tracker, not a nutrition tracker. It doesn't record quantities, calories, protein, fat, carbs, or fibre grams; it doesn't know whether your apple was a whole apple or a slice; it doesn't object if you log a plant on the basis of a single sprinkle. That's the design trade: in exchange for a logging time of about three seconds per plant, you give up everything except the count of distinct plants. If you also want macros, run a calorie app in parallel — the two answer different questions.
It's also not medical advice. The American Gut Project finding is an observational correlation between plant diversity and microbiome diversity in a self-selected sample, not a randomised controlled trial showing that 30 plants per week causes any specific health outcome. The bulk of the supporting evidence is consistent — diverse plant fibre, diverse short-chain fatty acid production, broadly favourable downstream effects on inflammation and metabolic markers — but the strength of "you must eat exactly 30 plants" is much weaker than the strength of "more plant variety, on average, looks helpful." Treat 30 as a memorable target, not a clinical threshold.
Features
- 120-plant library — six categories, every common entry, all browseable by chip.
- Search and category filter — type a name or tap a category to jump.
- Custom plant entry — anything missing can be typed in and saved back to the library.
- Radial progress ring showing plant points vs. target plus a per-category breakdown so you can see where to spend the week's last cheap point.
- Spector-rule scoring — every plant counts once a week; herbs and spices count at 0.25 by default (configurable to 0, 0.5, or 1).
- Weekly streak with current/best counters and 4/13/52-week milestones.
- 12-week history strip — each completed week as a small bar; tap any past week to view and edit its log.
- Adjustable target and week start so the tracker fits your shopping pattern and ambition level.
- Light and dark themes — auto-follows your OS preference.
- Local-only storage — nothing is uploaded; data lives in this browser only.
- One-page design — single static HTML file, no install, no app store.
Frequently asked questions
Why 30 plants per week?
The 30-plants-per-week target comes from the American Gut Project — the largest published crowdsourced microbiome study — which found that people eating at least 30 distinct plant types per week had measurably more diverse gut bacteria than those eating ten or fewer. Tim Spector, the King's College London genetic epidemiologist who co-led the project and runs the ZOE nutrition study, has spent the last decade popularizing the number as a practical, memorable target. Diversity matters because different gut microbes feed on different plant fibres and polyphenols, so the broader your plant intake, the broader the microbial ecosystem you support.
Do I need to create an account?
No. There is no sign-in, no email field, and no profile. Everything you enter is saved only in this browser's local storage on your own device. Nothing is sent to any server.
What counts as a plant?
Vegetables, fruits, whole grains, legumes (beans, lentils, chickpeas, peas, peanuts), nuts and seeds, and herbs and spices. The library has about 120 entries — apple, banana, kale, broccoli, oats, quinoa, lentil, chia, walnut, cinnamon, turmeric, and so on — and a custom-add button for anything missing. Mushrooms are technically fungi, not plants, but they ferment the same fibre and Spector includes them, so we do too.
How does the scoring work — what's the herbs-and-spices rule?
Every plant counts once per week — eating an apple Monday and again Thursday is one apple, not two. The five primary categories (vegetables, fruits, grains, legumes, nuts and seeds) score 1 point per distinct entry. Herbs and spices score 0.25 each by default — the standard Spector convention, on the reasoning that you typically eat them in smaller quantities. Twelve herbs and spices therefore add 3 points, not 12. The herb-and-spice weight is editable in settings if you want to count them at full weight or skip them entirely.
When does the week reset?
By default the week starts Monday and rolls over Sunday night, ISO-week style. You can switch the week-start day to Sunday in settings (common in the US). Whichever you pick, the current week's log carries forward each day until the reset, and once the reset hits a snapshot of the just-completed week is filed in your history strip. You can still open any past week from the history and edit its plant list — the week boundary is for scoring and streaks, not a hard lock.
How does the streak work?
Every completed week where you hit your target (default 30 plant points) counts toward your streak. Miss a target and the current streak resets to zero — best streak is preserved. The current week is in progress and only joins the streak at the end of the week if you cross the target. Milestones unlock at four weeks ("Month"), thirteen weeks ("Quarter"), and fifty-two weeks ("Year") of consecutive hits.
Should I worry if I only hit 20 plants in a week?
No. Twenty different plants is already a meaningful improvement over a typical Western intake — the American Gut Project's lowest band was ten or fewer, and the largest microbiome gains showed up between low and moderate variety, not between moderate and very high. The target is 30 because it's a round, memorable number that pushes you to include the small-quantity sources (herbs, seeds, beans) you would otherwise overlook. Treat the target as direction, not pass-fail.
What about repeats? Surely two different apple varieties are different plants?
Strict botanists count each variety. Spector pragmatically does not — he says "an apple is an apple" for everyday counting, since the bulk of the fibre and polyphenol differences are between species, not cultivars. This tracker follows the same convention: one apple entry per week, however many varieties you ate. If you really want to score by cultivar, use the custom-plant button to enter "Granny Smith," "Fuji," and so on as separate entries.
Is this a calorie or macronutrient tracker?
No. The tracker measures variety only — it does not record quantity, calories, protein, fat, carbs, or fibre grams. That's the design choice that makes the daily logging take ten seconds instead of ten minutes: you tap a plant when you've eaten it, and you're done. If you also want macro tracking, run a calorie app in parallel; the two answer different questions.
Can I add plants that aren't in the library?
Yes — the "Add custom plant" button at the bottom of the Add panel lets you type a name and pick a category. Custom plants are saved to your library and reappear in autocomplete the following week, so you only have to type each unusual item once. Use it for regional ingredients (jicama, daikon, longan, taro, samphire), specific varieties you want to track separately, or anything else missing from the default 120 entries.
Why is the herbs-and-spices weight a setting?
Because reasonable people disagree on it. Spector's 0.25 default acknowledges that a sprinkle of oregano isn't doing the same fibre work as a whole bowl of lentils. But some practitioners argue that polyphenol density in spices makes them worth full weight; others prefer to track herbs and spices separately and not have them count at all. The slider lets you set 0, 0.25, 0.5, or 1 — keeping the default unless you have a reason to change it gives you a number that matches the published challenge.
Does it work offline?
Once the page has finished loading, all tracking works without an internet connection. Reconnecting is only needed to load the page initially or to visit other pages on OmniAppHub.
What happens if I clear my browser data?
The tracker resets, because progress is stored locally rather than in an account. Switching browsers, switching devices, or using private browsing has the same effect.