Thursday, March 28, 2013

Early bloomers for Northern California.

Part of being a good land steward is to avoid the use of any pesticide and instead rely on natural methods of pest control.  I haven't used any insecticides in my garden, it doesn't mean I have no pests but I am able to keep them under control with various methods.  Healthy plants that are more resistant to pests are made by healthy soil so I keep the soil fertile with the addition of homemade compost, I also inter-plant edibles with flowers that attract beneficial insects, a plus is that the garden looks so pretty with all those early flowers.  Most insects, good and bad, overwinter only to reemerge in the spring.  To provide nectar for the hungry pest predators I have added many early blooming plants. Some were bought, some reseed themselves, some are perennials.

In my post on beneficials I mentioned few plants that bloom in mid spring, but the ones mentioned below have been blooming for few weeks already.

Just to name few plants blooming in my garden now: Borage, Borago officinalis, a self seeding edible annual, Biokovo Cranesbill, Geranium x cartabrigienses "Biokovo", a spreading groundcover that loves shade and blooms profusely, Juniper's beard, Centranthus ruber, another self seeding perennial plant, and Sweet alyssum, Lobularia maritima, which I bought since I don't have a greenhouse to propagate it.

Cerinthe major purpurascens, or Blue honeywort
I bought Blue hoenywort this year because it is beautiful and it a self seeding plant.  It belongs with Borage to the Boraginaceae family, both plants are loved by bees, which are already showing up in my garden.

Rue graveolens interplanted with mustard
Above are few perennial plants that will soon bloom and look so pretty together.  Anche l'occhio vuole la sua parte, even the eyes wants its part, we have to satisfy our sense of aesthetics, we say in Italian.

Mustard giant red, or Brassica juncea, flowers are delicious to tiny predator wasps
Last year I planted red giant mustard, soon to discover that its flavor is too strong for me.  I fell in love with the plant color however, and this year I used it as an accent in my veggie garden, and left the plants flower for the tiny predator wasp, who seems to like this type of flowers.  The color combination is stunning.

Mexican daisy, Erigeron karvinskianus, such a pretty and prolific bloomer.
Mexican daisy can self sow vigorously but it is easily controlled and is such a pretty and easy plant to have in the garden.  The plant above found its way in between the wood slabs of a tree planter.  I keep cutting it back every year and it comes back better than before.

Tanacetum parthenium, or Feverfew
Feverfew is one of those super plants to have in the garden, not only for the beneficials but as the name implies for its medicinal value, looking at it makes me happy.

Happy Spring!

Sunday, March 3, 2013

The Soil Food Web

I always knew that plants need good soil to thrive, I didn't know, however, how important the soil food web is in maintaining the health of plants until recently.  After I took a class on soil, and started reading more about this fascinating subject, I became convinced of the importance of the complex network of organisms found in soil.

Do you know how many critters live in a teaspoon of soil...take a wild guess.  There are over one billion bacteria, few yards of fungal hyphae, thousands protozoa, and few dozen nematodes in each teaspoon of healthy garden soil.  They all contribute to the breakdown of organic material so that it becomes available to plants to absorb through their roots.  Fungi eat bacteria, tiny mites eat fungi, earthworms eat mites, etc., they all produce waste, then die and return to dust, so the cycle continues.  But what was discovered relatively recently makes it even more interesting; certain fungi create associations with plant roots and enhance their capability to absorb nutrients through their filaments, or hyphae.  Moreover, plants produce chemicals called exudates, i.d. food, to keep the good microbes near their roots happy and thriving.  Fungi also produce substances that inhibit other organisms from growing near roots, therefore defending plants from pathogen attacks.

The soil food web is really important in controlling plant diseases.  Certain fungi will predate on nematodes that would enter the plant roots and eventually kill the plant.  Competition for nutrients in a healthy soil will also contribute to keep pathogens under control.   When soil microorganisms are killed by non sustainable practices some pathogens will proliferate so the use of more pesticides is seen as necessary.  Moreover the breakdown of organic material won't happen, so more synthetic fertilizers are applied and a vicious cycle will ensue.  The good news is that soil has the amazing capability for recovery and it can happen within few years, depending on the amount of abuse a soil has taken. Synthetic fertilizers leach from the soil really quickly so it is necessary to apply more of them compared to organic fertilizers or compost, which break down more slowly.  Not to mention that synthetic fertilizers are derived from petroleum, which there is less of it so their cost has been increasing in the last decade.  Organic fertilizers' price has not increased at the same rate on the other hand.

Another positive effect the soil web has is on the soil structure.  The soil microorganisms produce excretions to move around or create aggregates to live in, these secretions function as a soil glue keeping tiny soil particles bound together.  Burrowing animals contribute by creating pathways that help soil oxygenation and water penetration, and they also spread the nutrients around.  Thanks to growing knowledge on the soil microorganisms, and many scientific studies being conducted at various universities, a growing movement of no till methods to cultivate the soil has emerged in the last decade.  The principle behind it is that if soil is mulched and plenty of organic material is added to it, the soil food web will take care of the rest, including keeping the soil nice and soft with the action of the many critter that inhabit it.  Tilling disrupts the complex soil food web, by inverting the soil layers and exposing many microorganisms to the wrong conditions.

Elaine Ingham the SFW Queen

Elaine Ingham is a well known soil scientist and works at the Rodale Institute. She is a big proponent of the no till methods

Elaine is also doing great research on areated compost tea, which I find fascinating and it deserves a post on its own.

For more reading about this  subject, you can find a great description of soil microorganisms here, together with more articles on soil, at the Sustainable Agricultural Research and Education (SARE).

To learn more about this amazing system I highly suggest the book Teaming with Microbes, which gives a great overview on the soil food web, soil science, importance of mulching, restoration, and how to increase your soil fertility with home brewing compost tea.

Another book worth reading is The Soul of Soil Building, a soil building guide.
Roots Demystified is another great read on plant root systems.

In other words: only fertilize with organic compost (best your own), don't till, protect the soil by adding mulch (I see another post coming on mulch), and if you are so inclined brew your own compost tea (it is cheap and quick).