Plant Care Troubleshooting

Plant Care Troubleshooting

When to Use

Use this skill when:

• A user reports specific visible symptoms on a plant -- yellowing, browning, wilting, spots, distortion, discoloration, or unusual growth patterns -- and wants to understand why
• A user suspects a specific problem (overwatering, underwatering, pests, disease) but wants confirmation and a concrete treatment plan
• A user's plant is declining gradually or crashed suddenly and they do not know where to start
• A user wants to differentiate between two look-alike problems (e.g., spider mite damage vs. nutrient deficiency; overwatering vs. underwatering -- both cause wilting)
• A user asks about nutrient deficiency symptoms, interveinal chlorosis, or the visual signatures of macro- or micronutrient imbalances
• A user has already treated a plant problem once but the plant has not improved, and they want to reassess the diagnosis
• A user reports pest sightings or suspects pest damage on garden or houseplants
• A user's plant has survived but shows lingering symptoms (e.g., scarring, permanent leaf curl) and wants to know if recovery is possible

Do NOT use when:

• The problem involves turf grass, lawn patches, or sod -- use lawn-care-schedule instead
• The user wants to plan a new garden bed, design a planting layout, or select companion plants -- use vegetable-garden-planning
• The user is asking about growing vegetables from seed or crop rotation planning -- use vegetable-garden-planning
• The problem involves large tree health requiring arborist-level diagnosis: canopy dieback from fungal vascular disease (oak wilt, Dutch elm disease), root girdling, trunk wounds from equipment damage, or tree removal decisions -- these require in-person professional assessment
• The user has questions about human or animal health symptoms, even if they are plant-adjacent (e.g., "my child ate a leaf -- is it toxic?") -- refer to poison control or a veterinarian
• The user needs lawn overseeding, fertilization schedule design, or irrigation planning -- use lawn-care-schedule
• The user wants a full seasonal pruning plan or hedge trimming schedule rather than health problem-solving -- this is garden maintenance, not diagnostics

Scope clarification: This skill diagnoses plant health problems only. It covers houseplants, garden ornamentals, container plants, herbs, shrubs, and small woody plants. It does not provide medical, veterinary, or toxicological advice.

Process

Step 1: Gather the Minimum Diagnostic Dataset

Before forming any hypothesis, collect all of the following. Missing even one field -- especially watering frequency or soil moisture -- leads to incorrect diagnoses. Ask the user directly if any fields are absent.

• Plant identity: Species name, common name, or physical description (leaf shape, size, growth habit, whether it vines, rosettes, has thick succulent leaves, etc.). If the user cannot identify it, proceed to the identification sub-process in Edge Cases.
• Primary symptom: The single most noticeable problem. Yellowing? Wilting? Spots? Distortion? This is the diagnostic anchor.
• Secondary symptoms: Additional changes that accompany the primary symptom. Sticky residue? Webbing? Drooping? Smell?
• Location of symptoms on the plant: New growth (apical tips, youngest leaves) vs. old growth (lower, older leaves) vs. entire plant vs. one side only. This single factor eliminates half the diagnostic possibilities immediately.
• Timeline: Did this happen overnight or over weeks? Sudden onset suggests temperature shock, drought crisis, or chemical damage. Gradual onset suggests chronic mismanagement, slow-progressing disease, or nutrient depletion.
• Watering habits: How often, how much, and -- critically -- how the user decides when to water (by schedule vs. soil feel). Ask whether water pools in the saucer or drains freely.
• Soil moisture right now: Ask the user to press a finger 2 inches into the soil and report whether it is wet, moist, or dry.
• Light conditions: Hours of direct sun per day, compass direction of the nearest window (south-facing = most light, north-facing = least in the Northern Hemisphere), or outdoor exposure (full sun, part shade, dappled light under trees).
• Pot type and drainage: Does the pot have drainage holes? What material (terracotta dries faster than plastic or glazed ceramic)? How old is the potting mix?
• Recent changes: Moved, repotted, fertilized, treated with pesticides, subjected to a weather event, brought indoors for winter, recently purchased.
• Fertilization history: What product, what frequency, and when was it last applied. Fertilizer burn and nutrient deficiency are mirror-image problems that look similar but require opposite responses.

Step 2: Apply the Symptom Location Filter

The location of symptoms on the plant is the single most powerful initial filter. Apply this before consulting the full symptom table.

Symptoms confined to OLD GROWTH (lower, older leaves):

• Overwatering or root rot (most common)
• Nitrogen deficiency (mobile nutrient -- plant cannibalizes old leaves first)
• Natural senescence (if only 1-2 leaves drop occasionally, this is normal)
• Root-bound pot reducing nutrient uptake

Symptoms confined to NEW GROWTH (shoot tips, youngest leaves):

• Iron, manganese, zinc, or copper deficiency (immobile micronutrients -- cannot be redistributed from old tissue)
• Calcium or boron deficiency (also immobile)
• Thrips or broad mite damage (pests that feed preferentially on soft new tissue)
• Herbicide damage (affects emerging tissue first)

Symptoms on ALL LEAVES uniformly:

• Severe drought stress
• Root rot at advanced stage
• Systemic disease (viral mosaic, vascular wilt)
• Significant soil pH imbalance locking out multiple nutrients simultaneously

Symptoms on ONE SIDE or in PATCHES:

• Sun scorch (sun-facing side)
• Cold damage (side nearest a window in winter)
• Pest colony (local infestation)
• Mechanical damage or chemical contact

Step 3: Run the Full Symptom Diagnostic Table

Match the user's specific symptom profile to the table below. Use the Key Differentiator column to separate look-alike diagnoses before proceeding to a treatment recommendation.

Leaf Color Symptoms:

Structural and Growth Symptoms:

Step 4: Conduct Pest Identification

Only move to pest diagnosis if the user reports: visible insects, webbing, sticky honeydew, stippling, frass (insect droppings), distorted new growth, or shot-hole damage. Do not assume pests without physical evidence.

Houseplant and Garden Pest Reference:

Step 5: Assess Root Health When Root Problems Are Suspected

Root rot is the most frequently missed diagnosis because users do not want to disturb their plant. If any of these signs are present -- wilting with wet soil, persistent yellowing of lower leaves, mushy stems at the base, foul smell from the pot, or a plant that has been consistently overwatered -- guide the user through root inspection:

Root Inspection Protocol:

• Water the plant lightly (just enough to loosen soil) 24 hours before inspection if soil is bone dry and roots would be brittle
• Tip the pot sideways and gently slide the root ball out -- do not yank from the stem
• Brush away loose soil and examine the roots directly
• Healthy roots: white to light tan, firm, smooth texture, mild earthy smell
• Borderline roots: brown but still firm -- these are often viable but stressed
• Dead/rotten roots: dark brown to black, soft and slimy when squeezed, strong foul odor, disintegrate when touched

Root Rot Treatment Protocol:

• Using clean, sterilized scissors or pruning shears (wipe with 70% isopropyl alcohol), trim all rotten roots back to healthy tissue
• If the rot extends into the stem (crown rot), cut back to firm tissue even if significant stem material must be removed
• Optionally apply a light dusting of sulfur powder or cinnamon (both have antifungal properties) to the cut root surfaces
• Allow the trimmed root ball to air-dry in a shaded location for 30-60 minutes -- this allows cut surfaces to begin callusing and reduces the chance of reinfection
• Repot in fresh, sterile potting mix -- never reuse the old mix, which harbors Pythium and Phytophthora spores
• Choose a pot with drainage holes that is no more than 1-2 inches larger than the trimmed root ball (excess soil holds moisture that overwhelmed, reduced roots cannot absorb)
• Do not fertilize for 4-6 weeks after root rot treatment -- damaged roots cannot process fertilizer, and salt accumulation will burn recovery tissue
• Water very sparingly for the first 2 weeks: allow the top 2 inches to dry completely, then water just enough to moisten the root zone

Soil pH Quick Reference: Nutrient lockout due to incorrect pH is one of the most underdiagnosed plant problems. Most houseplants and garden ornamentals thrive in a pH of 6.0-6.8. Test with an inexpensive probe or paper test kit.

To lower pH: amend with elemental sulfur (garden beds, slow-acting), acidifying fertilizer, or sulfuric acid-based products for containers. To raise pH: lime (calcium carbonate) or dolomitic lime (also adds magnesium).

Step 6: Formulate the Diagnosis

Apply the following confidence framework before presenting a diagnosis:

High Confidence: Three or more symptoms point to the same cause, the pattern matches the species' known vulnerabilities, and the growing conditions logically explain the problem (e.g., wet soil + lower yellowing + mushy roots = root rot; high confidence).

Medium Confidence: Two symptoms align with one diagnosis, conditions are consistent, but one data point is ambiguous or missing (e.g., yellowing lower leaves + overwatering suspected but roots not inspected). State what confirmation test would elevate confidence.

Low Confidence: Only one symptom is present, the user cannot provide watering or light details, or the plant is unidentified. Provide a ranked list of top three possibilities with differential tests for each.

Present the most likely diagnosis first. Always provide at least one alternative and a specific test to differentiate between them.

Step 7: Deliver the Treatment Plan and Prevention Protocol

Treatment steps must be time-sequenced and species-aware. Generic advice ("water less") is insufficient. Provide:

• The immediate action to take today
• The recovery window expectation (most plants show improvement in 2-4 weeks if treatment is correct)
• The monitoring criteria (what the user should look for to confirm recovery vs. continued decline)
• Adjustments to the long-term care routine that prevent recurrence
• A clear "When to Discard" threshold -- some plants are not recoverable, and the user should be given that information honestly rather than pursuing treatments that will not help

Output Format

## Plant Diagnosis: [Plant Name / Species]

### Symptom Summary
| Field               | Detail                                              |
|---------------------|-----------------------------------------------------|
| Plant type          | [Common name + scientific name if known]            |
| Primary symptom     | [Most visible problem]                              |
| Secondary symptoms  | [Additional observations]                           |
| Symptom location    | [New growth / old growth / all over / one side]     |
| Timeline            | [Sudden onset vs. gradual / days vs. weeks]         |
| Watering habit      | [Frequency, method, soil moisture at time of report]|
| Light conditions    | [Hours, direction, intensity if known]              |
| Pot and soil        | [Drainage, pot material, age of mix]                |
| Recent changes      | [Repotted, moved, fertilized, weather event, etc.]  |
| Fertilization       | [Last application, product type, frequency]         |

---

### Diagnosis: [Primary Cause -- Specific Name]
**Confidence:** [High / Medium / Low]
**Diagnostic reasoning:** [3-5 sentences tracing each symptom to the diagnosis. Reference the specific data points the user provided. Explain WHY these symptoms together indicate this cause rather than others.]

---

### Alternative Diagnosis: [Second Most Likely Cause]
**Why it was considered:** [1-2 sentences explaining what symptoms overlap with the alternative.]
**How to rule it out:** [Specific test: check soil pH, inspect root color, look for webbing, etc. One concrete action the user can take right now to confirm or eliminate this alternative.]

---

### Treatment Plan
| Priority | Step | Specific Action | When |
|----------|------|----------------|------|
| Immediate | 1 | [Exact action with quantities, tools, technique] | Today |
| Immediate | 2 | [Follow-up immediate step] | Today |
| Short-term | 3 | [Recovery management action] | Days 3-7 |
| Short-term | 4 | [Monitoring check] | Week 2 |
| Ongoing | 5 | [Adjusted care routine] | Ongoing |

**Recovery window:** [Realistic timeline -- most plants show first signs of improvement in X weeks. Full recovery typically takes X months.]
**Monitoring criteria:** [What the user should see that confirms the treatment is working. What would signal that the treatment is not working and reassessment is needed.]

---

### Nutrient or pH Adjustment (if applicable)
| Nutrient / Amendment | Product Type | Rate | Frequency |
|---------------------|-------------|------|-----------|
| [e.g., chelated iron] | [Foliar spray / soil drench] | [oz per gallon, per sq ft] | [Weekly / monthly] |

---

### Prevention Plan
- **Watering adjustment:** [Specific rule for this plant: e.g., "Water when the top 2 inches of soil are dry, approximately every 7-10 days in summer and every 14-21 days in winter"]
- **Light optimization:** [Specific light requirement: lux range, window direction, grow light specs if needed]
- **Soil and drainage:** [Specific mix recommendation and drainage requirement]
- **Fertilization schedule:** [Product type, NPK ratio guidance, frequency, seasonal adjustments]
- **Environmental control:** [Humidity, temperature range, air circulation notes]

---

### When to Discard
[Specific, honest assessment of the point at which recovery is unlikely. Include: percentage of root loss, extent of stem/crown damage, or duration of decline that makes survival improbable. Where possible, provide a propagation-from-survivors option -- stem cuttings, leaf propagation, or division -- so the user does not lose the plant line entirely.]

Rules

1. Never diagnose from a single symptom. Yellow leaves alone could mean overwatering, underwatering, nitrogen deficiency, iron chlorosis, root rot, viral infection, or natural aging. Require at least two corroborating data points before forming a diagnosis. State this explicitly if the user provides insufficient detail.

2. Watering and soil moisture must be assessed before any diagnosis. Overwatering and underwatering together account for the majority of houseplant emergency visits. Ask about soil moisture RIGHT NOW (finger test) before assuming any nutrient or pest problem.

3. Symptom location on the plant is the most important filter -- apply it first. Old-leaf symptoms indicate mobile nutrient problems or chronic overwatering. New-leaf symptoms indicate immobile nutrient deficiencies, pH lockout, or pest damage to tender tissue. Never skip this filter.

4. Always provide a specific confirmation test alongside every alternative diagnosis. Saying "it could also be nitrogen deficiency" is insufficient. Say "rule out nitrogen deficiency by checking that the soil drains freely and the stems are firm -- if both are true, do a water-only flush and apply a balanced fertilizer in 7 days; if the yellowing reverses, nitrogen was the cause."

5. Treatment specificity is non-negotiable. "Water less" fails the user. The correct instruction is: "Allow the top 2 inches of soil to dry completely before watering, approximately every 10-14 days in normal indoor conditions. Press a finger 2 inches into the soil -- if it feels moist, wait. If it feels dry and the pot feels lighter than usual, water deeply until water drains from the bottom hole."

6. Pest identification requires physical evidence before treatment. Do not recommend insecticide applications unless the user has confirmed insect presence visually or through sticky trap catches. Insecticide application without pest confirmation stresses the plant unnecessarily and kills beneficial insects.

7. Do not recommend imidacloprid or systemic neonicotinoids on plants that flower or are accessible to pollinators outdoors. For indoor use where no pollinators are present and systemic control is needed (severe mealybug, scale infestations that resist topical treatment), imidacloprid soil drench is acceptable. Always note this restriction explicitly.

8. Root rot treatment requires pot and soil replacement -- not just reduced watering. Pythium and Phytophthora spores persist in old potting mix and on pot walls. Reusing contaminated soil after root rot treatment causes immediate re-infection. Always recommend sterilized fresh mix and a clean pot (washed with a 10% bleach solution, rinsed thoroughly).

9. Fertilizer burn and nutrient deficiency are opposite problems that look similar. Marginal leaf burn with white soil crust = salt accumulation from excess fertilizer; flush soil with 3x pot volume of clean water. Pale uniform growth with no soil crust = deficiency; begin a balanced fertilizer at half label rate. Applying fertilizer to a plant with fertilizer burn dramatically worsens the problem.

10. Give honest prognosis, including discard thresholds. A plant with more than 80% root rot, crown rot into the vascular tissue, or viral systemic infection is not recoverable through any treatment the user can perform at home. Telling a user to keep treating an unrecoverable plant wastes time and delays replacing it. Always offer a propagation alternative (stem cutting, division) where physically possible so the plant line can continue.

11. pH correction precedes nutrient supplementation. If soil pH is out of range, adding more fertilizer will not correct a lockout condition -- the nutrients are present but chemically unavailable. Diagnose pH first; amend pH second; then fertilize if needed. Applying chelated iron is the fastest way to address iron chlorosis while pH correction takes effect (chelated iron bypasses pH sensitivity).

12. Edema and overwatering have opposite treatments despite looking similar. Edema (corky blisters on undersides of leaves) is caused by irregular watering and low transpiration, not by the plant drowning. Improving light and air circulation treats edema. Do not mistake edema for a fungal infection or pest damage.

Edge Cases

1. Plant shows multiple severe symptoms simultaneously (yellowing + wilting + spots + leaf drop) When a plant crashes across multiple symptom categories at once, prioritize root investigation first. The vast majority of multi-symptom catastrophic failures trace to root rot or complete root desiccation -- both of which deprive the entire plant of water and nutrients simultaneously, causing systemic failure. Inspect roots before diagnosing multiple independent problems. If roots are healthy, assess each symptom cluster independently: the plant may have acquired two separate problems (e.g., fungal leaf spot from splashing water combined with underwatering from a schedule disruption). Treat the most life-threatening issue first (water balance), then address secondary issues once the plant stabilizes.

2. Plant was recently purchased, moved, or shipped and is now declining Newly purchased and recently relocated plants frequently show dramatic distress: leaf drop, wilting, yellowing -- all normal within the first 2-4 weeks. This is acclimatization stress or transplant shock caused by the transition from a high-light, high-humidity greenhouse environment to a lower-light, lower-humidity home environment. The plant is reducing its leaf mass to match available resources. Management: establish consistent conditions immediately; do not fertilize for 4-6 weeks (roots cannot process it); do not repot until the plant shows 2-3 new leaves of healthy growth. If leaf drop continues past 4-6 weeks or the stem becomes soft, re-evaluate for a true disease or pest problem.

3. Outdoor plant in an unknown growing season or after a weather event Outdoor plant problems are heavily confounded by weather. Before diagnosing disease or pest issues, ask: Was there a frost in the past 2 weeks? A heat event above 95°F? Heavy rain followed by standing water? Hailstorm? Cold damage looks like bacterial infection (brown, water-soaked tissue); heat and drought stress looks like spider mite damage; hail damage looks like shot-hole disease. If weather was extreme recently, the diagnosis leans toward physical or temperature damage rather than pathogen activity. Most weather-damaged plants recover on their own if the underlying environmental stressor is removed and the plant is otherwise healthy.

4. Edible plant with a disease or pest problem -- food safety concern Users with herb gardens, fruiting container plants, or kitchen garden vegetables often ask whether affected produce is still safe to eat. Provide plant safety guidance only, not dietary advice. General principles: remove and discard visibly diseased tissue (fungal or bacterial lesions); do not consume leaves with active pest colonies (honeydew and sooty mold make produce unpalatable and may harbor pest excrement); produce from the same plant that shows no visible disease symptoms is generally safe to consume after washing. Advise washing all homegrown produce thoroughly before eating regardless of disease status. If the user asks about plant toxicity to humans, direct them to poison control services -- this is outside the scope of this skill.

5. User cannot identify the plant Do not refuse to help when the plant is unidentified. Ask the user to describe: approximate plant height, leaf shape (round, oval, elongated, lobed, compound), leaf surface texture (smooth, waxy, hairy, thick/succulent), growth habit (upright, trailing, rosette, vining), flower color and shape if applicable, and where they obtained the plant. Most common houseplants can be reliably identified from these features. Cross-reference against most common indoor plants: pothos, philodendron, snake plant, ZZ plant, peace lily, fiddle-leaf fig, monstera, dracaena, rubber plant, spider plant. If the plant remains unidentified, apply general broad-spectrum troubleshooting for the most likely stress type based on conditions, and note that identification would allow more specific guidance.

6. User has already treated the plant and it is not improving Re-diagnosis is needed. Ask: What did you treat for, what specifically did you do, and how long ago? Then assess whether the original diagnosis was correct (re-examine symptoms through the diagnostic table) and whether the treatment was correctly applied. Common failure modes: treating for underwatering when root rot was the real cause (adding water accelerates rot); applying neem oil in direct sunlight (causes leaf burn); using insecticidal soap at too high a concentration (above 3% solution damages plant tissue); repotting a plant that needed pruning, not more soil. Revise the diagnosis based on how the plant responded to the first treatment -- a plant that got worse after watering is almost certainly overwatered, not underwatered.

7. Viral infection suspected (mosaic, ring spot, necrotic patterns) Viral plant diseases have no treatment. If the symptom pattern includes irregular mosaic yellowing with leaf distortion, ring spots, or necrotic line patterns that do not match any nutrient deficiency or overwatering profile, consider viral infection. Confirming features: symptoms are random and asymmetric (not following the old-growth/new-growth pattern), the plant has not responded to any nutritional or watering corrections, and multiple plants nearby show similar symptoms. Management: remove and bag the infected plant (do not compost); clean all tools with 70% isopropyl alcohol; control aphids and other sap-sucking insects that vector viruses; do not propagate from infected plant tissue. Be clear with the user: there is no cure, and the plant must be discarded to prevent spread to other plants.

8. High-value or sentimental plant in severe decline When a user indicates that a plant is irreplaceable (a cutting from a deceased family member's garden, a decades-old specimen, a rare cultivar), elevate the response priority toward salvage before discard. Explore all propagation options before recommending discarding: Can a single healthy stem cutting be taken and rooted in water or propagation mix before root rot claims the whole plant? Can the remaining healthy tissue be air-layered? Can leaves be used for propagation (succulents, African violets, begonias)? Even if the original plant cannot be saved, preserving genetic material through propagation is meaningful and should be offered as an option in all severe-case diagnoses.

Example

Input: "I have a peace lily that has been in the same spot by a north-facing window for two years. It was doing fine until about three weeks ago. Now the leaves are turning yellow -- mostly the older lower ones -- and a few leaves are drooping even when I water it. The soil feels kind of wet when I check it, and I've been watering it every Sunday no matter what. There's also a faint smell from the pot. I haven't fertilized it in about six months."

Plant Diagnosis: Peace Lily (Spathiphyllum wallisii)

Symptom Summary

Diagnosis: Root Rot from Chronic Overwatering (Pythium / Phytophthora spp.)

Confidence: High

Diagnostic reasoning: Four independent data points converge on root rot as the primary cause. First, watering on a rigid weekly schedule without checking soil moisture is the most common cause of chronic overwatering in container plants -- a peace lily in a north-facing window in autumn or winter requires water only every 10-21 days as light intensity and temperature drop. Second, the yellowing is confined to lower, older leaves -- a classic pattern for overwatering and root oxygen starvation, in which the roots cannot supply nutrients to the plant and the plant sacrifices older foliage. Third, wilting despite wet soil is the definitive sign that roots are no longer functional: a plant with healthy roots does not wilt in moist soil. Fourth, a foul odor from the pot is direct evidence of anaerobic decomposition -- rotting root tissue. Together these four factors make root rot the diagnosis with high confidence. The 2-year-old potting mix is a contributing factor: potting mix degrades over 12-18 months, losing its porous structure and retaining water much longer than fresh mix.

Alternative Diagnosis: Nitrogen Deficiency

Why it was considered: Lower-leaf yellowing is also a signature of nitrogen deficiency, which is plausible given six months without fertilization.

How to rule it out: Nitrogen deficiency does not cause wilting in wet soil, does not produce a foul odor, and produces firm (not mushy) stems. Remove the plant from its pot and check the roots. If roots are white and firm, nitrogen deficiency is the primary diagnosis and fertilization is the correct treatment. If roots are brown, slimy, or disintegrating, nitrogen deficiency may be a secondary contributing factor but root rot is the primary problem -- and fertilizing a plant with root rot will cause further damage, not improvement.

Treatment Plan

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