Утром мы купили семена моркови и сделали первую грядку у забора.

Утром is the instrumental singular of утро and is often used adverbially to mean in the morning or, depending on context, this morning.

Russian very often uses a bare time word like this, without a preposition:

• утром = in the morning
• вечером = in the evening
• днём = in the daytime
• летом = in summer

So Утром мы купили... is a very natural way to begin a sentence with a time setting.

Sometimes Russian can leave subject pronouns out, but here мы is useful because past tense plural forms like купили and сделали do not show person.

So купили by itself could mean:

• we bought
• you all bought
• they bought

Because of that, мы helps make the subject clear. If the context already made it obvious, Russian could omit it, but including it is completely normal.

That ending marks the past tense plural.

In Russian past tense:

• singular masculine: купил
• singular feminine: купила
• singular neuter: купило
• plural: купили

The same pattern works for сделать:

• сделал, сделала, сделало, сделали

Since the subject is мы, both verbs are plural: купили and сделали.

Both verbs describe completed actions:

• they bought the seeds
• they made/prepared the first garden bed

That is why Russian uses the perfective verbs:

• купить instead of покупать
• сделать instead of делать

If you used the imperfective forms покупали and делали, the focus would shift more toward process, repetition, or background activity rather than a finished result.

Семена means seeds, so the plural makes sense naturally in this context. You usually buy multiple seeds, not just one.

Here it is the direct object of купили, so it is in the accusative plural. Since семена is inanimate, its accusative plural looks the same as the nominative plural.

Its dictionary form is:

• singular: семя = seed
• plural: семена = seeds

Моркови is in the genitive singular and means of carrot, so семена моркови literally means seeds of carrot, which English translates more naturally as carrot seeds.

This is a very common Russian pattern:

• семена моркови = carrot seeds
• семена помидоров = tomato seeds
• кусок хлеба = a piece of bread

So the second noun often goes into the genitive to show what kind of thing the first noun is.

Because грядку is the direct object of сделали, it must be in the accusative singular.

The basic nominative form is:

• первая грядка = the first garden bed

But after сделали, it becomes:

• первую грядку

Both the adjective and noun change because Russian adjectives agree with the noun in gender, number, and case.

Since грядка is feminine singular, the accusative forms are:

• первая → первую
• грядка → грядку

Yes, literally it means made a garden bed, but in natural English it often means something like:

• prepared a garden bed
• made the first planting bed
• dug/laid out the first bed

Russian сделать is very broad and often covers actions that English expresses with more specific verbs. So сделали первую грядку does not necessarily mean they built something from scratch in a dramatic way; it can simply mean they prepared the first plot for planting.

The preposition у takes the genitive case.

So:

• nominative: забор = fence
• genitive: забора

У забора means by the fence, next to the fence, or near the fence.

This is a very common construction:

• у дома = by the house
• у окна = by the window
• у дороги = by the road

Russian word order is fairly flexible, and this sentence could be rearranged without changing the basic meaning. For example:

• Утром мы купили семена моркови и сделали первую грядку у забора.
• Мы утром купили семена моркови и сделали первую грядку у забора.

The version you have starts with Утром, which sets the time first and sounds very natural. Russian often puts the most topical or scene-setting information near the beginning.

So the word order here is normal, but not the only possible one.