Learn Spanish (Spain): Teníamos un huerto al lado de la casa y cultivábamos tomates. - We had a vegetable patch next to the house and we grew tomatoes.

This sentence perfectly matches your current lesson on describing a situation in the past. We are setting a scene and talking about how things used to be over an ongoing period (having a vegetable patch and growing tomatoes), rather than an action that started and finished at a specific moment.

Why does cultivábamos have an accent mark? Do all verbs in this tense get one?

For regular -ar verbs in the imperfect tense (like cultivar), only the nosotros (we) form gets an accent mark: cultivábamos. This is to keep the spoken stress on the correct syllable. Notice that for -er and -ir verbs like tener, every imperfect form gets an accent on the i, which is why we also see one in teníamos.

Could I use jardín instead of huerto for a garden?

Not if you are growing tomatoes! While English speakers often use 'garden' for both, in Spanish, a jardín is a decorative garden with flowers or grass. A huerto is specifically a vegetable patch or an orchard where you grow food.

How exactly does the phrase al lado de work?