Monday, July 14, 2014

Rain garden II - The costs

Part I summarizes my rain garden construction process.  I made the mistake of not pricing out everything before beginning the project. Before you commit to a rain garden, you should probably estimate the costs by choosing your garden size, determining whether (and how much) soil will need to be replaced, and either spending a couple hours calling local companies for materials pricing (large jobs) or checking a garden supply store (small jobs).  Also, be sure to check whether your locality provides monetary help.  Your local soil conservation district is a good place to find that out.

The vast majority of our costs, and a lot of the time commitment, arose because our site was heavy clay and all the soil had to be replaced.  Our rain garden is about 220 square feet.  We dug out the clay to 3-4 feet down because soil maps indicated that this depth would hit a better draining layer of soil.  This meant we had to remove and dispose of 30 cubic yards of clay and replace it with new soil.  Disposing of clay didn't cost us directly, since we used it to build up low areas rather than having it hauled away.

The materials prices I list below are typical for my area and for the volumes I was purchasing.  Plant costs were lower because I propagated some myself and was given others for free.  Costs would be about triple if I bought everything at plant sales.

Blue flag iris bud in the rain garden.  (Picture taken in May.)
Monetary costs:
  • Mini backhoe rental, 1 weekend (including delivery/pickup) - $300
  • Replacement soil, 30 yd (incl delivery) - $1300
  • Hardwood mulch, 13 yd (incl delivery) - $400 (Only about 25% is for the rain garden itself.  50% is to help stabilize disturbed areas where we disposed of clay, and the remainder is for other projects.)
  • Grass seed and straw - $30 (For parts of yard that were disturbed and/or where we disposed of clay.)
  • Plants - $170
  • Seeds and supplies to propagate more plants - $20 (Mainly spent on small plastic pots.)
  • Satellite dish reinstallation - $100 (It was originally located in the middle of our rain garden site.)
  • Digging out 30 yd of clay with mini backhoe and moving it to roughly the right location - 13 hrs
  • Preparing locations to receive clay - 8 hrs (Removed spilled concrete from house construction, and driveway gravel that had washed into low spots.)
  • Raking clay smooth after it was dumped by backhoe - 5 hrs
  • Rearranging new soil after it was delivered - 7 hrs
  • Propagating and tending plants destined for rain garden - 6 hrs (Spread over many months so not a big deal.)
  • Internet/phone research to source equipment and materials - 3 hrs
  • Building berm on downhill side of garden - 2.5 hrs
  • Mulching garden - 1 hr
  • Planting - 4.5 hrs 
  • Repairing damage after first rainstorm - 1 hr
  • Not listed:  Book/internet research on rain gardens and plants; shopping for plants (since these were the fun/hobby parts of the project)
  • Also not listed:  Further cleanup of areas where clay was disposed (mulching, reseeding, transplanting)
Tools we used:
  • Miniature backhoe (rented)
  • Stakes, string, and spirit levels - ensuring that bottom of garden is flat and that berm/edges of garden are all at the same height
  • Shovel
  • Garden rake
  • Trowel - for planting smaller plants
  • Mulch fork
  • Work gloves - makes a huge difference in number of blisters incurred
  • Garden hose - deciding and marking perimeter of garden before digging
  • Watering can

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