Clay Auger Sizes: Which Auger for Which Job
| Size | Auger | Best for in clay |
|---|---|---|
| 2" | Versatility Auger | Bare-root trees, shrub saplings, plugs, deep feeding |
| 3" | Everyday Auger | Bulbs, annuals, 4" pots, planting standing up |
| 4" | Large Bulb Auger | Large bulbs, perennials, bedding plants |
| 7" | Gallon Pot & Post Hole Auger | 1-gallon pots, 4×4 posts |
| 8" | 8 Inch Auger | Several bulbs in one hole, 2-gallon pots, posts |
| 9" | Extra Large Earth Auger | 6×6 posts, 2-gallon and larger pots |
Pick the Heavy Duty - Clay & Rocky option where it's offered; the 8" and 9" augers come standard with a heavy-duty tip. Not sure of the width? See the auger size guide.
Best Post Hole Digger for Clay Soil
For fence and deck posts in clay, use the Heavy Duty Gallon Pot & Post Hole Auger (7") for 4×4 posts or the Extra Large Earth Auger (9") for 6×6 posts. Run them on a high-torque 60V cordless drill; see drills for augers. Our post hole digging guide covers the rest.
How to Dig a Hole in Clay Soil
Pick the right day. Squeeze a handful of soil. If it forms a wet, sticky ball, wait for it to dry a little. If it crumbles to dust, water the area the night before.
Drill in short bursts. Drill a few inches, then lift the auger out while it spins to clear clay from the flights. Repeat until you reach depth.
Let the auger do the work. Keep it upright, start slowly and don't lean on the drill.
If it binds, stop. Release the trigger, reverse briefly to free the auger, clear the clay and carry on in shorter bursts.
More tips in How to Drill Holes in Clay Soil, or watch an auger dig through Georgia red clay.
FAQs
What is the best auger for clay soil?
A Heavy Duty auger in the width your job needs: 3" for bulbs, 7" for 1-gallon pots and 4×4 posts, 9" for 6×6 posts. See the 7" auger dig through rocky clay soil.
Do I need the Heavy Duty version for clay?
If clay or compacted ground is your normal soil, yes. On our 2" and 3" augers, the Heavy Duty tip is made from military-grade abrasion-resistant material. On 4" and larger augers, the Heavy Duty tip and blades are replaceable.
Can I replace a worn auger tip?
Yes, on 4", 5", 7", 8" and 9" Heavy Duty augers. Replace the heavy-duty tip or the blades instead of the whole auger.