Skill: germination-tracker

# Skill: germination-tracker

## Purpose

Analyze germination test results, identify lots with poor or declining germination rates, compare rates against category thresholds, and recommend actions such as re-testing, increasing seeding rates, or disposing of lots.

## Germination Rate Fundamentals

### Rate calculation

```
rate_pct = seeds_germinated / seeds_tested * 100
```

A test is only meaningful if `seeds_tested >= 10`. Tests with fewer seeds should be noted as potentially unreliable.

### Category thresholds

| Category | Minimum acceptable % |
|----------|---------------------|
| vegetables | 75 |
| herbs | 70 |
| flowers | 65 |
| grains | 80 |
| cover_crops | 75 |
| other | 70 |

A variety can override these with `min_germination_pct` on the variety record.

### Germination flag values

| Flag | Meaning |
|------|---------|
| ok | Most recent test is at or above threshold |
| poor | Most recent test is below threshold |
| not_tested | No tests recorded for this lot |

## API Calls for Germination Analysis

### All tests for a lot

```
GET /api/germination?lot_id=:id
```

Returns tests sorted by `test_date` descending. First item is the most recent test.

### All tests for a variety (across all lots)

```
GET /api/germination?variety_id=:id
```

Use this to spot trends across multiple lots of the same variety.

### Average rates by variety

```
GET /api/analytics/germination-rates
```

Returns per variety: average rate across all lots, flag if below threshold.

## Trend Analysis

To detect declining germination in a lot:

1. Fetch all tests for the lot: `GET /api/germination?lot_id=:id`
2. Sort by `test_date` ascending
3. Compare consecutive tests

Declining trend pattern:
- 3 or more tests where each rate is lower than the previous

Example:
```
Oct 2024: 90%
Feb 2025: 85%
Jul 2025: 78%
```
This is a declining trend. Even though 78% is still above 75% threshold for vegetables, the trend warrants monitoring.

Falling below threshold is when the most recent test dips below the variety's minimum.

## Recommending Actions

| Situation | Recommendation |
|-----------|---------------|
| rate >= threshold | No action needed, continue normal use |
| rate < threshold, lot is fresh | Re-test with a new 25-seed sample. If confirmed poor, increase seeding rate by 1.5x |
| rate < threshold, lot is aging | Re-test. If confirmed, consider sourcing new lot. Use remaining stock at 2x seeding rate |
| rate < threshold, lot is expired | Dispose lot, do not plant |
| rate unknown (not_tested) | Schedule germination test, especially if lot is aging |

## Seeding Rate Adjustment

When germination is poor but seeds are still usable:

```
adjusted_quantity = planned_quantity * (threshold_rate / actual_rate)
```

Example: planned 15g, threshold 75%, actual rate 60%:
```
adjusted_quantity = 15 * (75 / 60) = 18.75g
```

Round up to nearest 0.5g. Verify the lot has sufficient stock before recording the planting.

## Identifying Lots That Have Never Been Tested

```
GET /api/lots?status=active
```

Filter where `germination_flag = 'not_tested'`. These lots have no germination history and should be prioritized for testing, especially if they are aging.

## Comparing Germination Across Lots of the Same Variety

```
GET /api/germination?variety_id=:id
```

Group results by `lot_id`. Compare average rates per lot. If one lot is consistently lower, it may be from a different source, stored differently, or from saved seed with lower viability.

## Germination Test Conditions

For reliable results:
- Use at least 20 seeds, ideally 25-40
- Test temperature should be 18-24C for most vegetables and herbs
- Grain tests can run at 20-25C
- Use wet germination paper or a moist paper towel method
- Count germinated seeds at the expected `days_to_germination` of the variety
- Record actual days to germinate even if different from expected

## Monthly Testing Schedule

Recommended testing cadence:
- Fresh lots (under half viability age): test once per year
- Aging lots (past half viability): test every 6 months
- Lots approaching expiry (within 90 days): test before each major planting

To find aging lots that are overdue for a test:

1. `GET /api/lots?status=active`
2. Filter for `viability_status = 'aging'`
3. For each, check if most recent `germination_test.test_date` is more than 180 days ago
4. List those lots as needing a test

## Reporting Pattern

To produce a germination status report:

```
GET /api/analytics/germination-rates
```

Format output:
```
Germination Status Report - Riverside Farm - Jul 20, 2025

PASSING (above threshold):
  Brandywine Tomato:  89% (min 75%) - Fresh - Last tested Jul 18
  Dent Corn:          91% (min 80%) - Fresh - Last tested Jul 5
  Lacinato Kale:      87% (min 75%) - Fresh - Last tested Jun 20

FAILING (below threshold):
  Butterhead Lettuce: 65% (min 75%) - Aging - Last tested Jul 15
    Action: Re-test, then increase seeding rate or source new lot
  Dill:               58% (min 70%) - Aging - Last tested Jun 28
    Action: Confirm with re-test; use 2x seeding rate or dispose

NOT TESTED (12 lots):
  Schedule tests for aging lots first.
```