El sustrato está húmedo.

The potting substrate is damp.

Breakdown of El sustrato está húmedo.

• estar: to be
• húmedo: wet
• el sustrato: the potting substrate

Questions & Answers about El sustrato está húmedo.

Why is it está and not es?

Because Spanish usually uses estar for a state or condition, and húmedo here describes the current condition of the substrate.

So:

• El sustrato está húmedo = the substrate is damp/moist right now.
• El sustrato es húmedo would sound more like you are describing it as inherently or characteristically moist, which is much less natural in this context.

For things like temperature, physical condition, wetness, dryness, cleanliness, etc., Spanish often uses estar.

What does el mean here, and do I need it?

El is the masculine singular definite article, meaning the.

So:

• el sustrato = the substrate

Yes, in this sentence you normally do need it, unless the noun has already been introduced in a structure where Spanish allows omission. In a simple standalone sentence, El sustrato está húmedo is the natural form.

Why is it húmedo and not húmeda?

Because húmedo has to agree with sustrato, and sustrato is a masculine singular noun.

Agreement works like this:

• masculine singular: húmedo
• feminine singular: húmeda
• masculine plural: húmedos
• feminine plural: húmedas

Examples:

• El sustrato está húmedo.
• La tierra está húmeda.
• Los sustratos están húmedos.