How Can I Prevent Damping Off When I Sow Seeds?

“How can I prevent damping off when I sow seeds?  That is my problem.” Question from Bev of Philadelphia, Pennsylvania

Answer: This is a problem that I have faced many times starting seeds in university greenhouses, professional greenhouses, and at home. Thankfully, the solution is pretty simple, and it all involves keeping everything clean. Let’s start by covering the sources of damping off disease.

What is Damping Off?

Damping-off is a disease of sprouting seeds and seedlings that is primarily caused by two soilborne fungi, Pythium and Phytophthora spp. They cause rot and death in developing seeds and seedlings, usually at the roots or base of tender developing stems. Damping-off is a problem when growers keep the soil too moist and the disease is present.

To keep damping-off from taking hold you need to start with good soil, clean pots, and follow up with smart care.

Sterilizing Mix and Pots

Disease-carrying mix is the biggest concern. I used to work in large-scale greenhouses where they used big heater/steamers to sterilize mix at a temperature just high enough to kill any soilborne diseases (around 180°F). This is essential for growers that reuse mix, but careful growers sterilize new mix, too. Why? Because the airborne spores of damping-off fungi can be practically anywhere –especially in places where plants are being grown.

Additionally, unused seed-starting mix, like Black Gold Seedling Mix, is typically produced in clean facilities and bagged pathogen-free. But, if bags tear in transport and/or bags are not stored properly, Pythium and Phytophthora spores can infiltrate. Bags of seedling mix should be lightweight (meaning no water from the outside has seeped into the bag) and without tears. Improperly stored open bags at home can also be a danger. If you are not certain of your mix’s cleanliness, then it’s time for home sterilization.

I sterilize seed-starting mix using this fast and easy method.

Ingredients: Seed-starting mix, a 9″ x 13″ cake pan, 1/2 cup water, aluminum foil, and an oven.

Directions: Preheat your oven to 180°F, fill your pan with seedling mix, sprinkle it with the water, cover the pan with the foil, and bake it for 30 minutes. After baking, remove the pan from the oven and allow the mix to cool before using.

These diseases can also hang out on dirty old pots, so in the greenhouse, we’d also wash used pots and trays really well in hot water with good dishwashing liquid and sometimes a dash of bleach. I do this at home as well.

Seed and Seedling Care

Aside from starting with clean soil and pots, it is essential to discourage wet soils when starting and growing seedlings. I generally keep newly planted seeds gently sprinkled with a bottle waterer (see video below), so the soil is never over saturated. Once my seedlings pop up, I bottom water by adding 1/4 to 1/2 inch of water to the water-holding trays every two to four days, depending on seedling size. It also helps to encourage airflow, to help soil surfaces dry more quickly, and keep trays warm with a heat mat.

These cultural practices will definitely kick your damping-off problem away for life!

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Bottle Gourds: Growing Ancient History

The calabash or bottle gourd (Lagenaria siceraria) has been valued worldwide since ancient times and believed to be one of the oldest plant introductions into the Americas. Early botanical research has long attributed the origins of American bottle gourds to Africa, believing specimens floated across the Atlantic to reach the New World, though some studies tell a different story. Regardless of their path of arrival, these versatile gourds were an asset to early American peoples.

Gourd Origins

Hand-painted gourds demonstrate Anasazi pottery patterns from the American Southwest.

Native to Africa and Asia, bottle gourds were first introduced to the Americas 10,000 years before cultivation. Most believe that they passively arrived at the New World via ocean currents from Africa, but a few researchers believe that human beings intentionally brought them as they moved eastward into North America. The gourd’s strong, lightweight shells would have been ideal for portable containers carried by nomadic peoples to the New World. Gourd shapes would later become the models for the first Native American ceramic vessels, which were heavier and preferred by more settled cultures.

Choosing seed from plants that produced larger or different-shaped gourds was an early example of selective breeding by human beings. Soon the fruits were far larger than their wild-type progenitors. Gourd variations made shapes suitable for canteens, dippers for drinking, ladles, and even storage containers. The sheer diversity of gourds grown today descends from human intervention.

Why Plant Gourds?

A dry gourd can be transformed with a simple wood burner to reflect ancient design.

In America, the love of gourd arts and crafts remains the chief reason this plant remains in cultivation. Learning to create with gourds is an age-old skill that’s fun to learn and even more rewarding if you grow your own gourds. Small-budget gardeners will find gourd art-and-craft costs next to nothing, and the results are highly coveted handmade containers and gifts.

Bottle gourds are a cousin of winter squash and just as easy to grow. Commercial growers let them ramble across fields of rich agricultural soils, demonstrating how much water and nutrition they need to mature, though they will tolerate high heat and moderate drought as the summer heats up.

Growing Gourds

Grow gourds on the fence surrounding your yard or vegetable garden.

Sow seeds in native soil enriched with Black Gold Garden Compost Blend and Black Gold Earthworm Castings to ensure plenty of microbes and fertility for big, strong gourds. Plant them outdoors after the threat of frost has passed, and give them plenty of space to grow.

Even if you don’t have space to cultivate them in a field, gourd vines are happy grown on fences and arbors, too. They thrive on chain link or woven field fence where their tendrils can hold on tightly. Gourds that hang tend to be far more symmetrical with rounded bottoms. It’s traditional to grow long-handled dipper gourds from overhead trellises for straight handles. Gourds are grown on the ground and set upright early make better stand-up pots and vases because their bottoms develop flat.

Gourd vines bear both male and female flowers, which are white and held on thin stems above the foliage. Unlike bee-pollinated winter squash, gourds are pollinated at night by moths. Male flowers are produced first and female flowers follow. Aficionados often pinch off some male flowers to force more female blooms to increase yield. Vines are allowed to die back at season’s end; then gourds are left in the field to cure naturally in the sun before storing for winter.

Curing Gourds

Animal effigies and African watermelon beads make this gourd jewelry box special.

When gourds mature, they are still quite heavy because the tissues contain a great deal of moisture. A gourd requires up to a year to dry out fully and become ready to make into containers. To speed the process, drill a few small holes in the top and bottom of a fresh gourd to help moisture escape. Cure gourds overwinter in a dry place, such as a garage or barn loft.

Some folks dip their gourds in a mild bleach solution prior to winter curing to discourage discoloring mildew and fungi. If molds do form, don’t try to remove them as this interferes with the gourd’s outer surface integrity and patina. Mold can be easily removed much later when the gourd is completely dry.

Gourds are commercially grown all over America, proving their universal appeal and utility. Autumn is the best time to see them in their natural state at pumpkin patches in the fall.

This year don’t stop with pumpkins, select gourds you’d like to grow, too. Come spring they’ll be dry, and their internal seeds will be ready to harvest. Plant first-year seeds to grow gourds for many years to come without spending another penny.

Cool It with Violas

In the garden, these old fashioned violas spread, mound and cascade through the cooler seasons.
In the garden, these old fashioned violas spread, mound and cascade throughout the cooler seasons.

I once worked for Roger’s Gardens Colorscape, a world famous nursery that installs fabulous annual color gardens for stately homes on the southern California coast. That experience taught me how to grow annuals for two seasons. In early summer, we’d plant the traditional marigolds and petunias that love the heat. Come September, it was time to tear out all those warm season flowers and fortify the beds with compost and fertilizer before installing our cool season annual palette. Violas were a favorite for gracing our gardens with intense color all winter long. Continue reading “Cool It with Violas”