Tuesday, November 13, 2012

Sow Cover Crops for a Healthier Soil

Photo from Vintage Garden Gal
Now that you pulled all the summer veggies, and hopefully put them in your compost pile, it is time to think about feeding the soil.  Your soil has been depleted by the fast growing summer vegetables and if you don't plan on growing any winter vegetables, instead of leaving your beds empty consider planting them with a cover crop.

Cover crops or green manure are a fast and cheap way to add nitrogen and organic matter to your soil.   Cover crops have been used for centuries to replenish the fertility of soil.  If you want more information than I am providing here visit this great guide from Cornell University, which is targeted more to growers but has a nice extensive list of plants used as cover crops.  Sadly it advises to kill the cover crops with an herbicide before tilling it in, wrong!

Photo courtesy of Mother Earth News
Winter or cool season cover crops are normally planted in the Fall, and albeit it is a little late for some cold winter regions, if you live in California you can still throw some seeds on the ground for a nice spring harvest.

Cover crops can have three functions, enrich the soil of nitrogen, increase the biomass of organic matter in your soil, and when harvested they can be added to your compost pile to work as a green manure. 

There are two types of winter cover crop, the nitrogen fixing legumes, and the grasses like rye.  Plants in the legume family add nitrogen to the soil through the actions of bacteria present in nodules on their roots.  Without getting too technical, the bacteria absorb the nitrogen present in the air, in a gas form, and transform it or "fix" it into a form that is absorbed by plants.   When the plant is harvested and the roots left in the soil, the nodules degrade and the fixed nitrogen is releases into the soil.  Cool season legumes include clover, vetch, alfalfa, and fava beans.  

Photo courtesy of KB seed solutions
Grasses and grains build the soil and boost fertility by adding organic material and loosening hard soil with their long roots, they also suppress weeds and control erosion.  Annual ryegrass, barley and oats are commonly used.

Depending on your particular soil situation you can use one type of cover crop or a combination if you want your cover crop to accomplish more than one of the above.  If you are unable to find cover crop seeds at some of your local nurseries you can find them online.  Bountiful Gardens offers cover crop seeds in bulk, while Peaceful Valley Farm & Garden Supply has many soil building cover crop blends.

Once you have your seeds, remove and compost any debry of the spent summer vegetables.  Loosen the soil with a spade, breaking any hard clumps, rake it smooth and spread the seeds according to the packet instruction (if you plant too many you can always thin them later).  Gently rake the seeds into the soil and cover with some straw.  Water well for the first week or so.  Once the seedling emerge you can water less, or not at all if you have plenty of rain.

It is very important to harvest the legume plants right when they start flowering, which depends on the region you live in, it could be as early as February.  Once the plant start flowering it starts using the nitrogen present in the nodules to produce its own seeds so for maximum nitrogen crop plants need to be cut down at the first blooming.  Depending on how depleted your soil is you can either cut down the whole plant and till it in the soil, or cut and compost the green part and leave the roots to decompose in the soil.  If you leave the whole plant in, cut it in smaller pieces, till it in the soil and cover it so the soil microorganisms will decompose it faster.  In two or four weeks you can follow it with your spring planting.  For grass crops the harvesting is less critical but plan on cutting the plants when they are six to eight inches tall and till them in at least a month before you plan on using the bed.  If the grasses are left too long they get more woody and will take a longer time to decompose.

Happy Gardening!

Sunday, September 23, 2012

Happy Fall and Two Plants for Late Season Blooms

Anemone hupehensis
I love the changing seasons.  Coming from northern Italy I remember clearly when we started wearing sweaters, it felt good after the hot and humid Venetian summer.  Where I live now we wear sweaters all year due to the fog, so I can't tell from the cold that the Fall is now on us.  Many people think that there are no seasons in California, but it is so not true, my garden looks more and more brown everyday, and few annual plants stopped flowering in spots where the sun doesn't reach anymore.  I started pulling some of the string bean plants and bought many winter veggie seedlings.

Nothing says it more than Fall is here than the Japanese anemone, or Anemone hupehensis.   After planting two plants I realized how invasive this plant is, but I decided to keep it because the flowers are so elegant and it eases the season transition with its beautiful flowers.

One thing I will miss during the upcoming months are the flowers I can pick fresh from my garden.  I am hoping for few more weeks of bloom and then it will be all over until March or April.

By far the plant in my garden with the longest blooming is the Mexican Sage, or Salvia leucanthaThe bees are still buzzing around it, and I expect at least another month or two of blooms.  This plant can send underground runners too so it has to be kept in check every few years, however it has virtually no pests and it attracts insect pollinators and hummingbirds love it as well.

Mexican sage in the background

Sunday, September 16, 2012

Collecting Seeds

My garden started looking a little unkept, leaves are turning brown, annual plants are dying, but as this is part of the cycle of life I am looking forward to a new season and get busy collecting seeds for next year's garden.

Seed collecting has been a passion of mine for some time, as far as I can remember actually.  It is the cheapest way to propagate and share plants, and to add to my plant collection.   When I see a flower head full of seeds I can't help it and bring some home.

Seed saving has been done since men discovered agriculture.  We call ourselves Homo sapiens, but we lost 93% of the crop varieties in just 80 years due to poor agricultural practices.  I am glad to see companies like Baker Creek Heirloom Seeds prosper.

It is true that some plants hybridize easily so if you collect the seeds you don't necessarily end up with the same flower color, but that could be the fun part.

Dead heading flowers channels the energy of the plant to produce new flowers instead of developing seeds, so it is a good practice in the garden.  However, towards the end of a plant life, and especially in the Fall, it is a good idea to let some flower heads fully develop seeds to collect them for next year planting.

Black eye susan

Birds, a key asset to any healthy gardens, need seeds to survive the winter so I let my sunflower heads on the plant and sometimes I get a nice surprise and see some cool action.

Seeds are ready when they look brown and dry and detach easily from the flower head.  Letting seeds dry for few days at room temperature will assure that no mold will develop when stored away.

Some plants spread easily so I try not to let too many seeds escape, but when they do, in the case of borage or kale, I embrace the bounty of little tender plants to quickly sautee for a healthy meal.

I collect many tiny containers for  seed storing, envelopes, little ziplock bags, spice jars, anything small that can be used.  A good way to reuse, repurpose everyday object.

Orange cosmo seeds
Orange cosmos

 These orange cosmos come from seeds I collected last year in a public park, so they cost nothing.

Purple Scabiosa seed head
I find the seed heads' shapes and colors really attractive as well.  The fuzzy seeds of the Bishop plants are an example of beautiful form.

Orlaya grandiflora or bishop flower
The first time I saw this flower, Orlaya grandiflora, at a local demonstration garden I became enamored of the delicate and elegant flowers.  It is used to attract beneficial insects like the tiny parasitic wasps that lay their eggs into aphids.  I later found the plant at Annie's Annuals, if the seeds are viable I won't have to spend a cent to have it again next year.

Orlaya grandiflora or bishop flower

More orange Cosmos

Cilantro flowers
Some plants are really prolific in their seed production, so I will end up with more seeds I can possibly use, but luckily there is a local produce and plant exchange in my town and some people share seeds as well.  A six-pack of cilantro plants I bought to attract beneficial insects produced so many seeds that I will be able to preserve some for cooking as well.

Cilantro seeds or coriander

Happy seed saving!

Sunday, May 6, 2012

Beneficial Insects

Bumble bee in action on Spanish lavender

As a good omen let's start with a post on beneficial insects, which play a vital role in gardens.

There are two types of beneficial insects, the pollinators, and the predators.  Both play an important role in the life of plants, and any garden should be planted to welcome both.  There are many ways to attract beneficial insects, the most important one is to avoid the use of insecticides which will kill not only your pest, but a wide array of good bugs.  Secondly, it is important to offer a food sources for the beneficial, flowers with lots of pollen for the pollinators, and plants native to the region to provide nectar for native pollinators.  Some insects go through a complete metamorphosis and the adult form may feed on nectar while the larva stage feeds on other insects, so by planting a good variety of flowers it allows for both insect stages to take place in your garden.

Ceanothus, an early bloomer CA native
I am sure many of you heard about the disappearance of honey bees. There are other pollinators that appear to be declining, like bumble bees.  Almonds are an example of a crop which is solely pollinated by bees, so you can imagine the incredible impact on the food industry should we lose pollinators.  For a while I considered introducing a hive of honey bees in the garden but recently I decided to promote the health of the native bees, and any other pollinator that visits my garden.  If you are interested in planting your garden to attract pollinators please visit the very useful site called Pollinator Partnership to find a detailed and free list of plants that you can use in our particular area.

Here what I am doing in my garden:
  • Use an integrated pest management practice should I find a pest in the garden
  • Inter-planting flowers like Cosmos and Calendula in my vegetable beds
  • Select plants suited to your climate so they will stay healthy
  • Use of proper plant cultivation to maintain the health of the garden
  • Use of an array of flowering plants both for bees and butterfly
  • Plant many native flowers to keep the native insects happy
  • Select plants to have flowers most of the growing season, from early spring to late fall
  • Leave some ground not mulched for ground nesting bees

Parsley left to bloom for beneficials
Please tell me what are you planting in your garden.

Happy Spring!