1. I lied and told him that you were a fine gardener.

2. I lied and I told him that you were a fine gardener.

3. I lied him that you were a fine gardener and I told him that you were a fine gardener.

4. I lied him and I told him that you were a fine gardener.

(What does #1 mean among the others? And are 'lying' and 'telling' happening at the same time?)

1 and 2 are approximately the same. 3 and 4 are incorrect.

Yes, lying and telling are happening at the same time.