I am a complete garden novice, but recently rotavated a quarter acre of land & am now raking out the weeds...the level of the garden has gone down a couple of inches...As I am on a zero budget, should I sieve out the old soil & bring the level up & then spray with weed killer? The soil is wet, bog soil with about 4-5 hours sun / day...What plants / shrubs can you advise to drink up the excess moisture?