SEED ORDERS OVER $100 SHIP FREE!

Septic Safe Seed Mix

$39.00 - $1,720.00

500 sq ft
$39.00
1000 sq ft
$56.00
1/8 acre
$226.00
1/4 acre
$431.00
1/2 acre
$861.00
1 Acre
$1,720.00

for Medium-Dry to Dry Soils & Full to Partial Sun
Are septic system planting stipulations getting you down in the dumps? Don’t let these rules back up your landscaping plans!

This Septic Safe seed mix has all the qualities to make that crappy site into something beautiful and beneficial. These species are rugged; they will thrive in the moisture-sucking gravel above tanks and leach fields, as well as withstand the additional heat emitted from below. Once established, this combination of plants averages 2 to 3 feet in height. The colorful flowers throughout the growing season will provide year-long interest and support local pollinators like butterflies, bees, and birds.

Native plants create tight-knit communities with entwined root systems that will prevent soil erosion while absorbing excess moisture and *ahem* nutrients: Nature’s original filtration devices. These plants perform well in full or partial sun and prefer to keep their roots dry; this means that, although some roots dig deep, they will not seek out the piping underground or clog up the works.

The doo’s and don’ts of planting over septic systems:
Don’t Doo:
Doo Doo:
Don't add a lot of additional soil
Doo install herbaceous, non-woody plants
Don't mulch heavily
Doo prioritize drought tolerant species
Don't irrigate or water excessively
Doo plant perennials (for minimal ground disturbance)
Don't compact the soil

Don't dig deeply or till

Don't fertilize 

*Site preparation methods like tilling, sod removal, or smothering over a septic system may be not be an option, especially if the soil over the septic is particularly sparse. To remove existing vegetation, herbicide or cycles of burning/interseeding may be the only option.

For seed mixes of 1/8 acre or less, we include a temporary cover crop at no additional charge.  ReGreen is a sterile, short-lived perennial wheat hybrid that can be planted spring or fall.

View the complete species list, including % by weight, under COMPONENTS. Although some of the native plants in this seed mix have ranges that extend beyond zones 3-7, the majority will do best in this zone range.  For more detailed information please see the RANGE MAP for each species. 

All mixes are subject to change without notice depending on availability of species.

Septic-Safe Seed Mix

by Prairie Moon® Nursery

12.72 lbs per acre | 175 Seeds per sq/ft

(FILTER PLANTS IN THIS SEED MIX)

WILDFLOWERS

Botanical Name (Common Name)

% by wt.

Artemisia ludoviciana (Prairie Sage)

0.12

Asclepias tuberosa (Butterfly Weed)

1.97

Asclepias verticillata (Whorled Milkweed)

0.49

Baptisia alba (White Wild Indigo)

0.74

Callirhoe bushii (Bush's Poppy Mallow)

0.98

Chamaecrista fasciculata (Partridge Pea)

15.72

Coreopsis lanceolata (Lance-leaf Coreopsis)

1.97

Crotalaria sagittalis (Rattlebox)

0.98

Dalea purpurea (Purple Prairie Clover)

2.46

Echinacea pallida (Pale Purple Coneflower)

1.97

Euphorbia corollata (Flowering Spurge)

0.49

Gentiana flavida (Cream Gentian)

0.49

Helianthus pauciflorus (Showy Sunflower)

0.98

Lupinus perennis subsp. perennis (Sundial Lupine)

2.46

Monarda punctata (Spotted Bee Balm)

0.98

Oenothera rhombipetala (Sand Evening Primrose)

0.49

Penstemon grandiflorus (Large-flowered Beardtongue)

1.97

Rudbeckia hirta (Black-eyed Susan)

3.44

Solidago nemoralis (Old Field Goldenrod)

0.49

Symphyotrichum laeve (Smooth Blue Aster)

1.72

Symphyotrichum oolentangiense (Sky Blue Aster)

1.08

Tradescantia ohiensis (Ohio Spiderwort)

2.95

Verbena stricta (Hoary Vervain)

1.97

Zizia aptera (Heart-leaf Golden Alexanders)

0.98

Total of WILDFLOWERS:

47.88 %

GRASSES, SEDGES & RUSHES

Botanical Name (Common Name)

% by wt.

Bouteloua curtipendula (Side-oats Grama)

22.01

Carex brevior (Plains Oval Sedge)

3.93

Carex molesta (Field Oval Sedge)

0.98

Eragrostis spectabilis (Purple Love Grass)

0.49

Juncus dudleyi (Dudley's Rush)

0.74

Schizachyrium scoparium (Little Bluestem)

22.01

Sporobolus compositus (Rough Dropseed)

1.97

Totals of GRASSES, SEDGES & RUSHES:

52.12 %

(FILTER PLANTS IN THIS SEED MIX)

Last updated 11/9/23

7 Questions asked on Septic Safe Seed Mix

What are the root depths for this mix? I thought several of the plants listed had deeper root systems than recommended for septic mounds.
Hi Diana, Many of the native plants recommended for planting above septic systems are deep-rooted. When planting deep-rooted species, the important thing is to avoid plants with thick woody roots and water-loving plants that will seek out the network of underground pipes. Though several of the species in this mix have deep roots, the roots will not tolerate the consistent moisture in the drain pipes.
Have you received approval from any municipal, county or state waste water management organizations that this is safe to use over septic. Here in Delaware they are recommending only grass and as a Master Gardener I am trying to promote the use of wild flowers. I will investigate how to get this approved, but was wondering if you have taken any steps in this direction?
Hi Judy, We created this mix following generally accepted recommendations by university extension services including these linked publications by Purdue University and the University of Minnesota. We have not sought any formal approval, and we encourage you to make sure you are in compliance with state and local regulations.
Hi, what's the best way to remove grass and prepare a septic field for planting this seed mix? I've read on several university extensions that it's a bad idea to use sheet mulch or deep bark mulch as they interfere with evaporation. What do you advise?
Great questions, Marion! Preparing a garden site for over an established septic system does require some thought. Smothering or solarization are not recommended, since these methods interfere with the system's functions. Removing the sod could be an option - verify with your septic system installer that there is enough clearance; you may need to add more dirt to maintain soil depth requirements. Applying chemical or organic herbicide is probably the best way to prepare the site.
When is the best time of year to plant the seeds? We’ve just had our leach field redone and I’m wonder if I can plant the seeds now or if I should wait until the spring. I live in zone 5 in New England.
Hi Melissa. Late fall is our preferred timeframe for sowing seed. Sounds like perfect timing!
Does this mix provide blooms from spring to fall and do I cut it back once winter hits for new growth in the spring?
Hi Kate. Yes, all of the pre-designed mixes you see on our website have spring-fall blooms, once mature. To see which flowers you get by month (April-Oct), go into the COMPONENTS tab, and then click on the FILTER PLANTS IN THIS SEED MIX link. That will take you to a back-end subcategory on the website that will list each individual species in the mix. From there you can use the bloom time, and other filters, on the left.

As for clean up - you can cut plants back late fall or early spring. We are fans of waiting until spring so overwintering insects and other wildlife can utilize your prairie. A small area can be raked off or mowed off early spring, but best maintenance would be a spring burn every other year or so, if you can get a burn permit in your area.

I am in zone 3. Last summer we had a mound septic tank replaced. They used composted wood chips appro 2 ft deep, seeded with low growing seeds. Last fall and this summer nothing grew except few weeds.
Hi Lowell. First year plantings can often look very discouraging; were you able to water the site at all? Was a cover crop included in the initial sowing? If the composted wood chips are lofty, it is possible the seeds worked their way down too deep to get the light and warmth they need to get going this spring. Please feel free to respond to this message; we can continue troubleshooting and hopefully get your site growing soon!
My soil is pretty acidic. Will this seed mix tolerate acidic soil, or would I need to raise the pH first?
Hi Lauren. The species included in the Septic Safe seed mix are very tolerant. Especially when grown from seed, these plants will adapt to soil they are in, as long as the sun and moisture conditions are a good match.

Native plant communities provide the inspiration for our seed-mix designs. All our mixes feature high seeding rates and a diverse balance of native species, which, when mature, will provide blossoms throughout the year. No matter what you want from a seed mix, you will need to make sure it fits the soil-moisture holding capacity and sun conditions of your site.

Establishment of the diverse native-plant communities represented in our seed mixes can take three to five years. The most critical process before planting is preparing the site by removing unwanted species and working to deplete the soil’s weed seed bank. *Some site preparation methods like tilling, sod removal, or smothering over a septic system may be not be an option, especially if the soil over the septic is particularly sparse. To remove existing vegetation, herbicide or cycles of burning/interseeding may be the only option.  

Find detailed site prep, planting and care instructions for our seed mixes through the following links:

ESTABLISHING A NATIVE SEED MIX - 3 YEAR PLAN

PLANTING INSTRUCTIONS FOR HAND SOWING A NATIVE SEED MIX

*PLEASE NOTE: we are a mail order nursery and have no retail facilities, but you may pick up your order if prior arrangements are made. Pick up orders are subject to **MN Sales Tax.

US Shipping & Handling Charges

SEED $100.00 and under: $5.00
Retail SEED orders over $100.00 ship free!

Custom seed mixes or discounted seed sales over $100, add 5% of the total seed cost
(for orders over $1,000 a package signature may be required)

BARE ROOT and POTTED PLANTS $50.00 and under: $9.00
over $50.00: 18% of the total plant cost. (For orders over $1,000 a package signature may be required.)

TOOLS and BOOKS have the shipping fee included in the cost of the product (within the contiguous US).

**We are required to collect state sales tax in certain states. Your state's eligibility and % will be calculated at checkout. MN State Sales Tax of 7.375% is applied for orders picked up at our MN location. Shipping & handling charges are also subject to the sales tax.

Shipping Season

SEED, TOOLS and BOOKS are sent year-round. Most orders ship within 1-3 business days.

BARE ROOT PLANTS are shipped during optimal transplanting time: Spring (April-May) and Fall (Oct). Some ephemeral species are also available for summer shipping. Since our plants are field-grown, Nature sets the schedule each year as to when our season will begin and end. We fill all orders, on a first-come, first-serve basis, to the best of our ability depending on weather conditions beyond our control.

POTTED PLANTS (Trays of 32/38/50 plugs and 3-packs) typically begin shipping early May and go into June; shipping time is heavily dependent on all the species in your order being well-rooted. If winter-spring greenhouse growing conditions are favorable and all species are well-rooted at once, then we ship by order date (first come, first serve). We are a Midwest greenhouse, and due to the challenges of getting all the species in the Mix & Match and Pre-Designed Garden Kits transit-ready at the same time, we typically can't ship before early May. Earlier shipment requests will be considered on a case-by-case basis.

*We are unable to ship PLANTS (bare root or potted) outside the contiguous US or to CALIFORNIA due to regulations.

Delivery

We ship using USPS, UPS and Spee Dee. UPS and Spee Dee are often used for expediting plant orders; they will not deliver to Post Office Box numbers, so please also include your street address if ordering plants. We send tracking numbers to your email address so please include it when you order.

FOR MORE DETAILED SHIPPING INFORMATION, INCLUDING CANADA SHIPPING RATES (SEED ONLY), PLEASE SEE 'SHIPPING' AT THE FOOTER OF THIS WEBSITE.

Details

Lbs/Acre
12.72
Seeds/Sq.Ft.
175
Sun Exposure
Full, Partial
Soil Moisture
Medium-Dry, Dry
Advantages
Pollinator Favorite: butterflies, moths, bees, wasps, beetles
USDA Zones
3-7
Catalog Code
SEPTIC