Plant Calculator

Spacing Multipliers

You can use the following formula to calculate how many plants you will need based on your "Spacing Multiplier".

Example: you want to cover an area of 120 square feet with a spacing of 10". The Spacing Multiplier for 10" spacing is 1.45. Multiply 1.45 x 120 and you get 174 plants needed.

Formulas for figuring square feet

Squares and rectangles - Length x width
Circle - 3.14 x radius squared

Hardiness Zone Map

• Hardiness zones are a general indication of cold hardiness and are not exact. Elevation and other factors may affect suitability of certain plants, we suggest that you consult your local cooperative extension or a local landscaper or garden center if you are on a fringe zone.
• Recommendations for sun and shade planting are included to help you choose plants for your specific location. In the south, some plants listed as full sun can be more difficult to establish than in cooler climates. Heat, rainfall and other climatic differences can affect young plants.

Equivalents

1 sq. yard = 9 sq. ft.
1 sq. ft. = 0.11 sq. yds.
1 sq. ft. = 144 sq. inches
1 acre = 43,560 sq. ft.
1 acre = 4,840 sq. yds.

1 cu. yd = 27 cu.ft or 22 bu.
1 cu. ft. = 4/5 bu.
1 1/4 cu. ft. = 1 bu.
1 cu. yd. = a 3 inch layer over 108 sq. ft.

1 cu. yd. will fill:

• 190 1 gal. cans
  
• 1225 4" pots
  
• 3000 2 1/4" pots
  

Groundcovers are capable of giving long lasting beauty and function, but their performance is only as good as the effort one puts into soil preparation.

The best way to improve soil is to add organic matter such as peat, compost or manure at a rate of 25-35% by volume into the planting area. If your soil is heavy clay, the addition of organic matter improves both drainage and aeration and also allows better root development. Liberal amounts of organic matter help sandy soil hold water and nutrients. Finely ground pine bark is also good.

Spread a 2 to 4 inch layer of organic material over the garden surface and plow, spade or till the top 6-12" when the soil is not too wet (to test, pick up a handful of soil and squeeze it - if it stays in a ball it is too wet, if it crumbles freely, it should be about right). If you are tilling the area for the first time, till half the depth on the first pass and the remaining depth on a second pass.

If you elect not to till, you can dig individual holes and fill under and around the plant with soil enriched as above. If you have many holes to dig (especially if you have rocky or compacted soil), consider using a plant auger - it can save you huge amounts of time and effort. Many augers can be operated in regular drills (check the product description to see what size drill is needed: 1/4", 3/8", ...). Bare root plants would be happiest with a 3" hole (2 3/4" or even 2 1/2" is OK if that is all you can get). Potted plants do best in a hole that is twice as wide as the pot, this means either a large auger (that might require renting a power landscaping auger) or you use a smaller auger and manually enlarge the hole after drilling. Many garden centers carry augers or they are readily available online.

Incorporate a complete fertilizer like 10-10-10 into the soil at the time of tilling or planting. For maximum growth, a high nitrogen fertilizer like 16-4-8 should be applied every 4-6 weeks after planting, beginning in early spring through late summer. In early fall and winter, apply 5-10-15 at recommended rate. After fertilizing, water the plants to wash fertilizer from foliage and avoid any burning of new growth. Avoid over-fertilizing, it can burn or even kill your plants. Fast growing plants and plants that produce an abundance of blooms can benefit from more fertilizer. [more information on fertilization]

For best results, incorporate a pre-emergent weed control herbicide into the planting area. Follow label instructions for the brand you choose. Be sure to check the label of the brand selected to assure applicability to the specific groundcover to be treated. Applying a 2-4" heavy top mulch will greatly assist weed prevention, erosion control and increase moisture retention.

Consider testing the pH (and perhaps even magnesium, phosphorus and potassium levels) of your soil and adjusting as needed during the tilling step. It's WAY more important to the health and growth rate of plants than most people realize. [more information on pH]

If you'd like to reduce your frequency of watering and risk of drought damage, consider adding Horticultural Grade Terra-Sorb (AKA Super-sorb) to your soil. It absorbs up to 200 times its weight in water and slowly releases it. It's non-toxic, non-hazardous to the environment, and compatible with fertilizer. Apply at a rate of 1 pound per 100 square feet for each 2 inches of depth by raking or tilling into the ground 2-4 inches (or mix 1/2 teaspoon into the soil under/around each individual plant).

Terra-Sorb is available at many garden supply stores and online in quantities ranging from 3 ounces to 40 pounds Terra-sorb's Material Safety Data Sheet and Product Directions

Planting Instructions

The best times to plant are spring and fall, when soil is workable and out of danger of frost. Fall plantings have the advantage that roots can develop and not have to compete with developing top growth as in the spring. Spring is more desirable for perennials that dislike wet conditions or for colder areas, allowing full establishment before first winter.

To plant container-grown plants: Prepare planting holes with appropriate depth and space between. Water the plant thoroughly and let the excess water drain before carefully removing from the container. Carefully loosen the root ball and place the plant in the hole, working soil around the roots as you fill. If the plant is root bound, separate roots with fingers. Continue filling in soil and water thoroughly, ideally protecting from direct sun until stable (if possible).

To plant bare-root plants: Plant as soon as possible after delivery. Prepare suitable planting holes, spread roots and work soil among roots as you fill in. Water well and ideally protect from direct sun until stable (if possible).