Understanding the Health Check Results

The five core metrics

Sproutcast's default pipeline set produces five metrics per capture. Here is what each one means in practice.

1. Plant area (% of frame)

The proportion of the image classified as plant foliage. Over time, this is your primary growth signal. A flat or declining area after weeks of captures usually means the plant has stopped growing — check light levels and nutrient supply.

This metric is only useful when the camera stays in the same position across captures. See the camera-tips guide for framing advice.

2. Chlorophyll index

Derived from the relative brightness of the red and near-infrared channels (approximated via the green channel on visible-light cameras). A high chlorophyll index (above 0.65 in Sproutcast's normalised scale) indicates healthy, nitrogen-rich foliage. Values below 0.45 correlate with nitrogen deficiency, overwatering, or root stress.

What causes it to drop:

• Overwatering / waterlogged roots (most common in houseplants)
• Nitrogen depletion in soil after 6–8 weeks without fertilising
• Insufficient light — leaves become pale as they reduce chlorophyll to save energy

3. Turgor pressure proxy

Measured via leaf edge sharpness (the variance of the Laplacian operator on the segmented leaf mask). A turgid, well-watered leaf has crisp, sharp edges. A wilting leaf has softer, less defined edges even before the droop becomes obvious to the naked eye.

This metric can give you a 12–24 hour early warning before visible wilting. Set a health alert threshold of 0.60 and you will get a push notification when leaves start losing turgor.

4. Dominant hue

The most common hue (in HSV space) within the segmented plant region. Healthy foliage typically sits in the 80–140° range (green). Yellowing pulls this toward 40–80° (yellow-green to yellow). Browning tips pull it below 40°.

5. Leaf colour uniformity

The standard deviation of hue values across the leaf mask. High uniformity (low std dev) means consistent colour — usually healthy. High variance can indicate: nutrient deficiencies showing as patches, sunburn, or early fungal spotting.

Setting alerts

Go to Plans → Edit plan and set threshold alerts for any metric. The default thresholds for a generic houseplant are: