Ni havas tiom da kompoŝto kiom da organika rubo.

Tiom ... kiom ... is a comparison pattern meaning as much ... as ....

So:

• tiom da kompoŝto = that much compost / as much compost
• kiom da organika rubo = as much as organic waste

Together, the sentence means that the amount of compost matches the amount of organic waste.

This is the quantity version of comparison. Esperanto uses:

• tiel ... kiel ... for as ... as with manner or adjectives
• tiom ... kiom ... for as much / as many ... as

So here the sentence is comparing amounts, not qualities.

Da is used for an unspecified quantity of something, especially with words like much, little, a lot, enough, and so on.

In this sentence:

• tiom da kompoŝto = so much compost / as much compost
• kiom da organika rubo = as much organic waste

You use da because kompoŝto and organika rubo are being treated as substances or quantities, not as countable individual items.

A useful way to think about it is:

• tiom tells you how much
• da links that quantity to the noun

So tiom da kompoŝto literally works like that amount of compost.

Because they are being used as mass nouns, like water, sand, food, or trash in English.

In Esperanto, when you're talking about an amount of a substance or material, the noun is usually singular after da:

• multe da akvo = a lot of water
• iom da mono = some money
• tiom da kompoŝto = that much compost

Even though the meaning may involve a large amount, Esperanto normally keeps the noun singular after da when it is a mass noun.

Here:

• kompoŝto = compost
• organika rubo = organic waste / organic trash

Both are understood as materials, not countable separate objects.

There are two reasons.

1. There is no direct object here after da

After da, the following noun does not normally take the accusative -n.

So you say:

• multe da akvo
• iom da pano
• tiom da organika rubo

not:

• multe da akvon
• tiom da organikan rubon

2. The adjective agrees with the noun

Because rubo is singular and not accusative here, the adjective stays the same:

• organika rubo

not:

• organikan rubon

So organika matches rubo, and neither one gets -n.

This is a very common learner question.

The full object is really tiom da kompoŝto. In Esperanto, when a phrase with da is the object, the accusative usually goes on the quantity word if it is marked at all, not on the noun after da.

So in principle, you may see:

• Ni havas tiom da kompoŝto.

and sometimes also:

• Ni havas tiomn da kompoŝto.

But the noun after da still does not get -n.

In modern usage, many speakers simply leave tiom without -n, especially when the meaning is already clear from word order. So the sentence as given is normal and natural.

The important thing for a learner is:

• do not say da kompoŝton
• after da, the noun itself normally does not take -n

Use kiom for quantity and kiel for manner/quality.

Here the sentence compares amounts, so Esperanto uses kiom:

• tiom da kompoŝto kiom da organika rubo = as much compost as organic waste

You would not use kiel here, because this is not about how something is done or what something is like.

Compare:

• Li estas tiel alta kiel mi. = He is as tall as I am.
• Mi laboras tiel kiel vi. = I work as you do / in the same way as you.
• Mi havas tiom da mono kiom vi. = I have as much money as you.

So kiom is the right word because the sentence is about amount.

Normally, no. The second da is needed because kiom is also expressing a quantity, and it needs to connect to the noun organika rubo.

So:

• tiom da kompoŝto kiom da organika rubo

is the normal structure.

Without the second da, the grammar would feel incomplete, because kiom by itself does not directly attach to the noun in this kind of phrase.

A good pattern to remember is:

• tiom da X kiom da Y

For example:

• Mi trinkis tiom da akvo kiom da suko.
• Ŝi havas tiom da tempo kiom da mono.

Yes. The structure tiom ... kiom ... normally expresses equality of amount.

So the sentence means that the amount of compost is equal to the amount of organic waste.

It is not saying:

• more than
• less than
• about the same

It is saying as much ... as ..., which suggests equal quantity.

If you wanted other comparisons, Esperanto would use different forms, for example:

• pli da ... ol ... = more ... than ...
• malpli da ... ol ... = less ... than ...

Yes. Rubo is a broad word covering ideas like trash, garbage, waste, or refuse, depending on context.

In this sentence, organika rubo most naturally means organic waste. That is probably the best translation because it fits the context of composting.

So although rubo can be translated in several ways, organic waste is the most natural choice here.

Because organika is an adjective modifying the noun rubo, and in Esperanto adjectives most commonly come before the noun.

So:

• organika rubo = organic waste

This is the normal word order.

Esperanto adjectives can sometimes come after the noun, but before-the-noun placement is the standard and easiest pattern for learners.

Also remember that adjectives agree with nouns in number and case. Here both are singular and have no accusative ending:

• organika rubo

To some extent, yes, because Esperanto word order is fairly flexible. But this version is the clearest and most natural for learners:

• Ni havas tiom da kompoŝto kiom da organika rubo.

If you changed the order too much, the sentence could become harder to understand, especially because the tiom ... kiom ... pair works best when the two parts are easy to match.

So while Esperanto allows flexibility, keeping the paired structure together is a good habit:

• tiom da X kiom da Y

You would usually add ne before the verb:

• Ni ne havas tiom da kompoŝto kiom da organika rubo.

That means We do not have as much compost as organic waste.

Notice that the comparison structure stays the same. Only the verb phrase changes.

This is a useful pattern to learn, because it is very common in Esperanto:

• Mi ne havas tiom da tempo kiom vi.
• I do not have as much time as you.