Mezclo la composta con el humus de lombriz.

In Spanish, the verb ending already tells you who is doing the action. Mezclo is the yo form of mezclar in the present tense, so it already means I mix.

That means:

• Mezclo = I mix
• Yo mezclo = I mix, but with extra emphasis on I

Spanish often leaves out subject pronouns unless the speaker wants contrast, emphasis, or clarity.

So this sentence sounds natural as:

• Mezclo la composta con el humus de lombriz.

If you said:

• Yo mezclo la composta con el humus de lombriz.

it would still be correct, but it might sound like:

• I’m the one who mixes the compost with worm humus or
• I mix it (not someone else)

Mezclo is the first-person singular present indicative form of mezclar.

Here is the present tense:

• yo mezclo = I mix
• tú mezclas = you mix
• él/ella/usted mezcla = he/she/you mix
• nosotros mezclamos = we mix
• ellos/ellas/ustedes mezclan = they/you all mix

So in the sentence, mezclo means the speaker is talking about a current or habitual action:

• I mix
• I’m mixing (depending on context)

Spanish simple present often covers both English I mix and I am mixing.

Spanish uses definite articles (el, la, los, las) more often than English does.

So where English might say:

• I mix compost with worm humus

Spanish often says:

• Mezclo la composta con el humus de lombriz.

Here, la composta refers to the material as a known substance, not necessarily a specific single pile. This is very natural in Spanish.

You will often see this pattern with materials and general things:

• Lavo la ropa. = I wash clothes / the clothes.
• Tomo el café sin azúcar. = I drink coffee without sugar.
• Corto la madera. = I cut wood.

So the article is normal and does not always translate directly into English.

Both the idea and the vocabulary can vary by region.

In much of Latin America, composta is a common word for compost. In some places, people may also use:

• compost
• abono
• abono orgánico
• compostaje (more often the process: composting)

So la composta is a valid and natural Latin American term.

A useful distinction:

• la composta = compost, the material
• el compostaje = composting, the process

Regional vocabulary matters a lot in gardening and agriculture, so learners may hear more than one version.

Literally, humus de lombriz means something like worm humus or humus of worm.

In natural English, it usually refers to:

• worm castings
• vermicompost
• worm humus

The phrase de lombriz tells you what kind of humus it is: humus produced by worms.

This de phrase works a lot like made from, from, or of:

• jugo de naranja = orange juice
• leche de almendra = almond milk
• abono de lombriz = worm fertilizer / worm compost

So humus de lombriz is a type of soil amendment associated with earthworms.

Spanish often uses the singular after de to name a type or category.

So de lombriz does not necessarily mean only one worm. It functions like a classification:

• humus de lombriz = worm humus / worm castings
• granja de pollo can mean a chicken farm type idea, even though many chickens are involved
• cepillo de dientes = toothbrush, even though you have many teeth

In other words, the singular can be generic.

You may sometimes hear plural forms in other contexts, but humus de lombriz is a standard set phrase.

The noun humus is masculine, so it takes el:

• el humus

Not every Spanish noun follows the most common ending patterns. Even though many masculine nouns end in -o and many feminine nouns end in -a, there are plenty of exceptions, especially with learned words and borrowed terms.

So this is simply a noun you should memorize with its article:

• el humus

That article is especially useful because it helps you remember the gender naturally.

In standard Spanish pronunciation, the h is silent.

So humus is pronounced roughly like:

• OO-moos

A few notes:

• The h is not pronounced.
• The stress is normally on the first syllable: HU-mus
• The Spanish u sounds like the vowel in food, but shorter and cleaner.

Also, this word is not pronounced like English hummus the food. In Spanish, humus in a gardening context is a different word and pronunciation pattern.

Con means with.

In this sentence, it shows what is being mixed together:

• Mezclo la composta con el humus de lombriz.
• I mix the compost with the worm humus.

This is the standard way to express mixing one thing with another:

• Mezclo agua con tierra. = I mix water with soil.
• Mezclan pintura con arena. = They mix paint with sand.

If you used y instead, it would just mean and, not necessarily that one thing is being mixed into the other.

Yes, absolutely. That is grammatically correct.

Both of these are natural:

• Mezclo la composta con el humus de lombriz.
• Mezclo el humus de lombriz con la composta.

The difference is mostly one of focus or presentation:

• putting la composta first highlights the compost
• putting el humus de lombriz first highlights the worm humus

English works similarly:

• I mix the compost with worm castings.
• I mix the worm castings with the compost.

Both are fine unless the context makes one sound more logical than the other.

It can mean either one, depending on context.

Spanish present tense often covers both:

• habitual action: I mix
• action happening now: I am mixing

So:

• Mezclo la composta con el humus de lombriz.

could mean:

• I mix compost with worm humus (in general / as a routine) or
• I’m mixing the compost with worm humus (right now)

If the speaker wants to strongly emphasize that the action is happening at this moment, Spanish can also use:

• Estoy mezclando la composta con el humus de lombriz.
• I am mixing the compost with worm humus.

But the simple present is still very common and natural.

Usually, yes. Lombriz commonly refers to a worm, and in gardening or compost contexts it usually means an earthworm.

Because the sentence is about compost and humus, a learner should understand:

• lombriz here = composting worm / earthworm

In everyday use, context usually makes this clear. If someone wanted to be more explicit, they might say:

• lombriz de tierra = earthworm

But in this sentence, just lombriz is perfectly normal.