A la tardor, la meva tieta vol collir els tomàquets del pati.

Yes. A la tardor is the normal Catalan way to say in autumn / in the fall.

• a = here it works like in / during
• la tardor = the autumn

Catalan often uses the definite article with seasons:

• a la primavera = in spring
• a l’estiu = in summer
• a la tardor = in autumn
• a l’hivern = in winter

So even though English often says just in autumn, Catalan commonly says a la tardor.

Because A la tardor is a time expression placed at the beginning of the sentence.

The basic sentence without that fronted phrase would be:

La meva tieta vol collir els tomàquets del pati.

When Catalan puts a time phrase first, a comma is very common:

• A la tardor, ... = In autumn, ...
• Demà, ... = Tomorrow, ...
• A vegades, ... = Sometimes, ...

It helps separate the introductory information from the main clause.

In Catalan, possessives are often used with the definite article:

• la meva tieta = my aunt
• el meu pare = my father
• la seva casa = his/her/their house

This is more normal in Catalan than in English. English says my aunt, but Catalan usually says the my aunt, literally speaking.

There are some situations where the article may be omitted, especially with close family terms in some contexts, but for learners, article + possessive + noun is the safest and most standard pattern.

Tieta means aunt.

In Catalan, tieta is a very common word. Depending on region and style, you may also see tia. Broadly speaking:

• tieta can sound a bit more familiar or affectionate in many contexts
• tia is also used and is perfectly standard

For a learner, it is enough to know that la meva tieta means my aunt.

Because Catalan, like English, uses one verb to express wanting and then an infinitive for the action wanted.

• vol = wants (from voler, to want)
• collir = to pick / to harvest

So:

• vol collir = wants to pick

This is directly parallel to English:

• She wants to pick tomatoes
• Vol collir tomàquets

A few examples:

• Vull menjar. = I want to eat.
• Volen sortir. = They want to go out.

Vol is the 3rd person singular present tense of voler:

• jo vull = I want
• tu vols = you want
• ell/ella vol = he/she wants
• nosaltres volem = we want
• vosaltres voleu = you all want
• ells/elles volen = they want

Here it matches la meva tieta, which is singular:

• La meva tieta vol ... = My aunt wants ...

Collir means to pick, to gather, or sometimes to harvest, especially fruit, vegetables, or flowers.

In this sentence, collir els tomàquets is most naturally:

• to pick the tomatoes

If the context is a garden or small number of plants, pick is usually the best English equivalent. In a larger agricultural context, it can also overlap with harvest.

Examples:

• collir flors = to pick flowers
• collir pomes = to pick apples
• collir tomàquets = to pick tomatoes

Catalan often uses the definite article where English does not.

So collir els tomàquets can mean:

• pick the tomatoes
• or in natural English, sometimes simply pick tomatoes, depending on context

In this sentence, the article suggests specific tomatoes, probably the ones growing in the patio/garden.

This is very common in Catalan:

• M’agraden els llibres. = I like books.
• Rento els plats. = I wash the dishes.
• Collir els tomàquets. = pick the tomatoes

So do not expect article use to match English exactly.

Del is a contraction of de + el:

• de = of / from
• el = the
• del = of the / from the

So:

• els tomàquets del pati = the tomatoes of the patio
• more natural English: the tomatoes from the patio or the patio tomatoes, depending on context

Other common contractions:

• al = a + el
• del = de + el

Yes, pati is related to patio, but the exact sense can vary depending on context and region.

It can mean:

• patio
• courtyard
• yard
• outdoor area attached to a house

So els tomàquets del pati probably means the tomatoes growing in the house’s outdoor space. In idiomatic English, you might translate it as:

• the tomatoes in the patio
• the tomatoes from the yard
• the backyard tomatoes

The best choice depends on the situation, but the Catalan word itself is straightforward.

Yes. That sentence is also grammatical.

These two are both fine:

• A la tardor, la meva tieta vol collir els tomàquets del pati.
• La meva tieta vol collir els tomàquets del pati a la tardor.

The difference is mainly focus:

• A la tardor, ... emphasizes the time first
• putting a la tardor at the end sounds more neutral

Catalan is fairly flexible with word order, especially for time expressions, though not completely free.

A few useful ones:

• tardor: the final r is pronounced lightly in most varieties
• tieta: roughly tye-ta
• vol: short, simple vowel; not like English vole
• collir: the ll is not an English l in many accents; pronunciation varies by dialect, but learners often hear something like ko-lyir or ko-yir
• tomàquets: the accent mark shows the stress falls on mà: to-MA-quets
• pati: roughly PA-ti

You do not need perfect regional pronunciation right away, but it helps to notice stress and the accented syllable in tomàquets.

The accent mark in tomàquets shows where the stress goes: to-MÀ-quets.

Catalan uses written accents to mark stress and sometimes vowel quality. For a learner, the most important thing here is stress:

• tomàquet = singular
• tomàquets = plural

Without paying attention to the accent, English speakers may stress the wrong syllable. The written accent helps prevent that.