Fern care

	How to Care for Your New Fern
Contents: [ General considerations \| Tree ferns \| Xeric ferns ]

General considerations

Plant hardiness. Know your zone! Before ordering, please know your USDA hardiness zone and check that the plant(s) are suited to where you live. (Our nursery is located in zone 9b).

Weather data from our nursery is available on these sites: Citizen Weather Observer Program (CWOP), MesoWest (University of Utah), PWS Weather, and Weather Underground. Our MADIS ID is D2408.

Water. Remove potentially-harmful chlorine from water used for irrigation with a carbon-block water filter. Outdoor filters are available which are designed to be fitted fitted to garden hoses.

(At our nursery, we happen to use several GH101 garden hose filters, manufactured by Pure Water Products, which are designed to take a standard 2.5" x 9.75" cartridge).

Fertilizer. Avoid artificial fertilizers. They are harmful to the environment and to soil dwelling organisms. It is also very easy to overfertilize with chemical fertilizers, which will result in damage to the plant.

Diluted fish emulsion is ideal as an organic fertilizer for most (but not all) fern species, and does not 'burn' plants.

Composting. You can save money, grow healthier plants, reduce the amount of garbage you produce, and benefit the environment by recycling household and garden organic 'green' waste into compost.

For composting purposes, redworms or red 'wriggler' worms (Eisenia fetida) are highly recommended. These worms are adapted to thrive in decaying organic material and are readily available for use in vermiculture. They are also sold as bait.

The nice folks at West Contra Costa Integrated Waste Management Authority have discounted compost bins available for West County residents. They may be purchased at the West County Resource Recovery Facility, 101 Pittsburg Avenue (just off of the Richmond Parkway). Call (510) 412-4500 to confirm availability, or see recyclemore. (Please note: cash or check only). There are a number of other discounted compost bin programs throughout the San Francisco Bay Area.

Mycorrhiza. Whenever a fern is potted, planted, or transplanted, treat the soil around the root system with a mycorrhizal inoculant.

All of the plants from our nursery are treated with MycoApply® Soluble innoculant. Please see Mycorrhizal Applications Inc. for further information.

Pest control. For insect pests, rather than using pesticides, use natural pest control such as ‘beneficial’ nematodes. Spraying the soil annually with the species Steinernema feltiae and Heterohabditis bacteriophora used in combination works well for a large range of insect pests.

Slugs and snails can be removed by hand, with population control by occasional application of an iron phosphate based product when necessary.

The vitamin B-1 myth. Article by Dr. Linda Chalker-Scott, Ph.D. Washington State University here

See further horticultural myths here

Tree ferns

Although the climate in the San Francisco Bay Area is suitable for many tree fern species, there are some special horticultural considerations. Irrigation is perhaps the most obvious, and during the three months of our normally dry summer season it is critical that tree ferns receive regular watering. This is sometimes done with sprinkler heads at the end of narrow vertical pipes reaching above each plant. As the tree fern gain height, the length of the pipe is adjusted accordingly.

Alternatively, the tree fern can be watered manually. Pour de-chlorinated water onto the center of the crown so that it runs down the trunk. On very hot days, hand-spray the trunk as required.

Fertilize with a very dilute solution (~1:16) of fish emulsion.

Soil. If you have a garden of heavy clay soil, typical of the Bay area, break up the soil and add a lot of organic matter in the form of the readily available redwood chips or shredded bark. This will improve the drainage and beneficially increase the acidity of the soil to the pH 5.5-6.5 range.

Soil should be moist, but well drained.

Frost. A further issue of concern is frost. The hardiness of tree ferns varies from species to species.

In January of 2007 an unusually severe frost wiped out three-quarters of California's citrus crop, so it pays to always be prepared! Horticultural fleece, which is readily-available in large sheets for covering crops, is ideal for protecting tree ferns.

Do not use an impermeable material to wrap or cover ferns. Doing so will prevent air from reaching the plant and trap moisture, which can cause the plant to rot.

To protect the roots of the plant and prevent the ground from freezing, a thick layer of redwood chips works well as an insulating layer. Do not smother the ground with an impermeable material.

Straw is also often used to insulate tree ferns from frost by gently packing it into the crown of the plant.

Withhold from watering the plant during excessively cold weather, when there is a chance of temperatures approacing freezing.

The growth rate of your new tree fern will vary by species, but environmental factors will also come into play.

We recommend keeping your tree ferns in a pot for the first 18 months or longer, until it develops large fronds and starts to show a trunk forming. Thus the plant can be moved easily if it is in an unsuitable spot, rather than having to transplant it. It is also easier to protect the plant while it is young, and it can be temporarily relocated indoors to protect it from frost if necessary.

Xeric ferns

Xeric (xeriphytic) ferns have evolved to thrive where one would not typically expect to find ferns growing; dry, rocky environments, often in full sun. This makes them perfect for xeriscaping (also known as water-conserving/drought-tolerant landscaping), and ideal companions for other plants which require little water, such as cycads and cacti.