Yellow leaves are a general alarm, not a diagnosis. Overwatering and underwatering can look identical at a glance; iron deficiency and root rot produce similar symptoms. The problem most videos share is listing causes without helping you rule them out one by one.
Short verdict
For the general question, start with the GARDEN TIPS 2020 episode. It runs through all ten mainstream causes in descending order and gives a specific remedy for each. If that does not match what you see, Fraser Valley Rose Farm adds two causes the others miss entirely — herbicide drift and plant virus — with real examples of both. Growers with tomatoes or peppers specifically will find the Geeky Greenhouse and Pepper Geek videos more directly relevant to their plant.
The ranking
1
Best overall
TOP 10 REASONS FOR LEAF YELLOWING AND LEAF BURNING / BROWNING WITH TREATMENT 🍂🍂
GARDEN TIPS · 9:22 · Sep 2020
GARDEN TIPS presents ten causes of leaf yellowing in descending order: natural ageing, pest attack, root-bound conditions, transplant shock, fertiliser overuse, high soil pH, temperature extremes, sunlight problems, improper watering, and nutritional deficiency including leaf chlorosis. Each cause comes with a specific remedy — Epsom salt at 5–10g per litre for transplant shock 2:40, neem oil every 15 days as a pest preventive 1:36, a soil pH gadget for diagnosing alkalinity 3:55, and a one-to-two minute drainage timing test 7:42.
Why it ranks here: This is the most complete single-video answer to the question as people actually type it. The descending-order structure means you start with the most likely cause and work outward. One practical sorting note at 8:40 — indoor plants lean toward overwatering problems, outdoor plants toward underwatering — is the kind of shortcut that saves real time when you are not sure where to look first. The treatment detail is also stronger here than in any comparable general video.
~9 min · all plants · ten causes with specific treatments
2
Best for unusual or persistent causes
8 Reasons why Plant Leaves Turn Yellow
Fraser Valley Rose Farm · 11:22 · May 2020
Jason from Fraser Valley Rose Farm walks through eight causes using potted and garden roses as examples, explicitly stating the advice applies to all plants. He shows live specimens for drought stress, nutrient deficiency (interveinal chlorosis), root damage from excess moisture or fertiliser, natural autumn variation, foliar fungus such as black spot, spider mites causing leaf bronzing, herbicide drift from a neighbouring property, and plant virus.
Why it ranks here: Two causes here appear in no other video in this pack. The herbicide drift section 8:49 shows orange-yellow discolouration with twisted new growth caused by spray from a neighbour's farm — a symptom that can genuinely stump a gardener who has already ruled out watering and nutrients. The virus section 9:25 shows irregular yellow patches on leaf margins and explains why the plant must go into the burn pile 9:47: pruners used on an infected plant can carry the virus to the next one 10:04. Eight named chapters let you jump directly to whichever cause you are testing.
~11 min · all plants · chaptered · includes herbicide and virus
3
Quick-scan alternative
LEAVES TURNING YELLOW? 10 TIPS to Fix Plant with Yellow or Brown Leaves | Leaf Chlorosis
GARDEN TIPS · 5:42 · Nov 2017
This earlier GARDEN TIPS episode covers the same ten causes in a five-and-a-half minute run-through, naming each and giving the headline fix. It flags leaf chlorosis as a 'deadly condition' that can affect a branch or the whole plant 4:43 — a severity note the 2020 episode handles more briefly.
Why it ranks here: If you have already watched the 2020 GARDEN TIPS episode and want a fast reminder, this shorter version covers identical ground. As a first watch, the 2020 episode is the stronger choice: this one moves quickly and goes into less depth on treatments. It earns its place as a useful second reference rather than a replacement.
~6 min · all plants · overview only
4
Best for tomato growers
Tomato Leaves Turning Yellow? How To Fix It Fast - Geeky Greenhouse
Geeky Greenhouse · 8:23 · Jul 2022
Geeky Greenhouse covers seven causes of yellowing on tomatoes — nitrogen deficiency, sun scald during the indoor-to-outdoor transition, overwatering, poor airflow, disease, aphids and thrips, and cold weather — using a live stressed plant throughout. The airflow section 3:27 is the most detailed of any video here: it covers bottom pruning to a foot off the ground, plant spacing at 24–36 inches, and sucker removal on indeterminate varieties.
Why it ranks here: Although the framing is tomatoes, the causes and fixes apply broadly to most fruiting garden vegetables. The cold-weather section 7:03 explains that stress sets in once temperatures drop below 50°F, worth knowing if you grow outside in a cool climate. Eight chapters mean you can skip directly to whichever cause you are investigating rather than watching end to end.
~8 min · tomatoes · chaptered
5
Best for pepper growers
Pepper Plant Leaves Turning Yellow? Common Causes & Solutions - Pepper Geek
Pepper Geek · 8:28 · Jan 2021
Pepper Geek covers four causes of yellowing on pepper plants using a live nitrogen-deficient plant as the central example. The video explains how to distinguish nitrogen deficiency — whole-leaf yellowing that moves upward from the base 1:36 — from magnesium deficiency, where only the tissue between the veins yellows while the veins stay green 2:12, alongside overwatering, cold-weather stress, and disease or pest damage.
Why it ranks here: The nitrogen-versus-magnesium distinction 2:06–2:17 is more clearly shown here than in any other video in this pack, and the live plant makes the difference visible rather than theoretical. Best watched once you are sure the plant in question is a pepper; for a broader first diagnosis, start with GARDEN TIPS.
~8 min · peppers · chaptered
