Maximizing crop in a Keyhole Garden

Even the smallest space can offer bounty! It just takes a little planning and forethought about the placement and choices of crops.

In this video below I explain how to use succession to plant vegetables close together knowing their days to maturity. For example when planting a long days to maturity crop such as broccoli a shorter crop such as radishes are planted right next to it. The intention is that the radishes will be eaten and long gone by the time the broccoli has grown large and covered the space.

In a nutshell, rows will be interspersed with long season next to a short season crop and then another longer season crop. Sowing lettuce next to carrots followed by radishes gives the lettuce and radish the room to grow, and adds a bit of cover for tender carrot seedlings as they get some size. Lettuce can be sown thickly and harvesting as baby greens can begin a few weeks after planting as lettuce matures after 30-45 days.

The same strategy can be used for the radishes, depending on the variety, as radishes can be thinned and harvested while small and tender and continuously until a larger size. French radishes can begin to be harvested at 2 weeks! If growing Asian daikon style radish (as mentioned in the video) it can take 50-60 days for full size and some large radish varieties can take 120 days. So keep that in mind when calculating succession growth as carrots take about 100-120 days to maturity.

Carrot seedling with radishes
Radishes are fast approaching harvest size and the carrots planted underneath will fill in the vacancies

Maximize the growing space as plants are growing. Don’t plant 3 adjacent rows of long season vegetables at the same time. There will be so much crowding that some of the plants will fail to thrive from lack of light and root room. And there will be more issues with mildew, aphids and other pests by crowding. Stagger planting times so that Broccoli is finishing as a new row is just beginning to replace. Plant frequently – eat frequently!

When using succession planting, it is important to add lots of compost and/or use liquid fertilizers (such as fish emulsion) to keep nutrients available at all times. Side dressing with compost during the season really works as does adding compost every time new plants are added. I like to start most seeds in six pack and transplant in as there is more control on the spacing over sowing in place.

Also, ROTATE THE CROPS! There will be less issues with pests if vegetables like onions and beets are not continuously grown in any one area. For example, onions are susceptible to onion root maggots that live in the soil. Planting onions in the same spot would give such a pest an a huge advantage. Leaf miners are another pest that love beets and Swiss chard. The life cycle is dependent on the ability of the destructive tunneling maggots to drop off the plant into the soil and then hatch into little flies that then lay eggs on the leaves. Good to know!

Beets grown in keyhole garden
This bed has leaf miners that have been tunneling in the beet leaves. I am using Spinosad and checking the leaves everyday to remove the eggs to break this pernicious cycle.

Replacing Mexican Feather Grass

Recently, a gardener asked what kind of ornamental grass would be good to replace her Mexican feather grass. She had just found out that it was on the California invasive species list and was alarmed that it was freely reseeding in her neighbors yard.

Mexican feather grass – Nassella tenuissima or Stipa tenuissima,  is a beautiful ornamental grass that is easy to grow. As a landscape grass, it has a fine movement in the gentlest breezes. But, it reseeds easily and abundantly, sprouting out of every crack in driveways, sidewalks and paths. For such an angelic wispy form, it is a true botanical thug in the garden!

Mexican Feather Grass
Mexican Feather Grass exhibits its tenacious side – this has sprouted from seed blown down the street a block away!

Why do the garden centers still sell this plant? Because it is popular and there are no laws to stop them. Mexican Feather grass is native to the south-western United States, northern Mexico and Argentina.

For this gardener, it was important that the replacement grasses have the same easy care and drought tolerance, and, have movement and upright form. We came up with this list that best suited the criteria and growing conditions of her garden as well as being non-invasive. As an added bonus several of these selections provide deep roots to stabilize slopes, create seeds for birds and food for insects.

‘Karl Foerster’ is tall and stately in a planting

Calamagrostis acutiflora ‘Karl Foerster’ Feather Reed Grass

‘Karl Forster’ is a striking, formal upright grass that turns golden as the season progresses. Like the Mexican Feather grass, it has that lovely motion in the breeze that can be so delightful in the garden. It has a distinct sound from other grasses when the seed stalks rattle together. Feather Reed Grass has been on the “It’s It” plant lists for a few years for good reason. As a natural hybrid of of C. arundinacea, and C. epigejos it can claim heritage to both natives of Asia and Europe. The seeded heads are sterile so there is little chance of unleashing another invasive grass in to the landscape.

On the Central Coast, this Calamagrostis is only semi-deciduous and can remain green through most of the year if it gets some dry season water. A little late fall – early winter trim of old growth can get it off to a good fresh start for the spring. As a grass, it does like a bit of fertilizer during the growing season. It will tolerate both clay and sandy soils, and, can become drought tolerant after establishing. Just an FYI – this grass will get up to 5 feet tall when it blooms unlike the Mexican Feather Grass!

Pink Muhly drought tolerant grass selection
Pink Muhly adds a burst of cloud pink to the garden when the seed stalks form

Muhlenbergia capilaris ‘Pink Muhly’

The ornamental value of this ‘Pink Muhly’ cannot be understated. It is a showstopper when in full pink cloud bloom. This grass has been featured in many garden spreads and does not disappoint. The pink heads fade to a tawny brown through the season at about 3 feet high. There is also a white cultivar – ‘White Cloud.’

This grass is semi-deciduous and can be given a haircut in the early winter unless the winter grayed color is desired. Pink Muhly requires good drainage so not a choice for heavier clay soils. As for drought tolerance, in the sandy soils a little summer water can go a long way to extend the show.

Drought tolerant tough Muhlenbergia rigens
Muhlenbergia rigens has great texture when planted in clumps

Muhlenbergia rigens Deer Grass

Deer Grass is a California Native (but not to all areas of California). That said it is extremely adaptive to most soils and conditions and can even take a bit of shade. It can easily grow under oak trees in dappled shade. This is a tough plant that can grow to 4 feet tall. The roots grow very deep and give this grass a great toe hold for drought conditions after establishment. A battery of Deer Grass can stabilize a soil bank equal to any large shrub! As another bonus, this grass feeds many birds and beneficial insects. Deer Grass deserves to be in more California-style gardens for its fountain like structure and shaggy evergreen form.

Still looking for something else?

Using native California grasses in the landscape can offer a unique fit to specific soils and growing conditions. There are many other native California grasses that have a place in the garden.

Here is a partial list that is worth a little research:

  • Bouteloua gracillis
  • Festuca californica
  • Festuca idahoensis
  • Carex – several species
  • Deschampsia caepitosa
  • Leymus triticoides
  • Nasella pulchra





Veggies on the coast

I want to grow veggies, but my soil is so sandy

Raised Beds

Bad soil does not grow good veggies. If you are planning to grow vegetables, creating raised beds allows you to control the growing medium and get to the good stuff (growing yummy things) faster. A raised bed will be warmer than growing directly in the soil. This adds HEAT for crops that may not like the cooler summer temperatures found on the coast.

A 4′ x 8′ bed is a good size – you should be able to reach in to the middle from either side. Depth should be greater than 12 inches or more. Cedar and redwood make long lasting wooden boxes. Recycling wood materials is another way to build beds. Just keep clear of railroad ties (creosote) or old painted boards (lead) to keep contamination out of your food supply! If you can get your hands on broken concrete, speed block, brick, roofing tile, rock, etc you can build free form beds to suit your taste. Or you can spare your back and try…

Straw Bale Gardens

Don’t laugh – it works. In fact straw bale gardening will save you so much time, labor and money, you will wonder why you did not do this years ago. There are many links online to sites that describe exactly how to create verdant rotting straw islands of goodness in your garden. Just do a search for “straw bale gardening.” When the season is over, you will have ready-to-use compost from the now reduced straw bale too.

Tomatoes growing in a straw bale
Like a raised bed, a straw bale will be warmer for roots—a great advantage for tomatoes on the coast

Because the straw bale IS the soil, you don’t need to build a wooden or concrete bed, import or amend soil, or constantly water sandy soil. After the straw bale(s) has been properly conditioned (rotted) compost is added on top and plants are grown directly into the bale(s). Crops that like the straw bale treatment include tomatoes, squash, pumpkins, cucumbers, and other summer veggies that could use a little more water and heat. For tomatoes, fish heads added down in the bottom of the hole with compost when planting have yielded good results.

What grows in the fog?

Do your research. Beefsteak tomatoes grow great in a greenhouse and specific little microclimates (lucky!) on the coast, but struggle in the cool July summers. Generally all the winter greens will do great. Beets, carrots, leeks, celery, parsley, bok choy, tatsoi, kale, cilantro, rutabaga, parsnip and mustard can grow almost year round. Seasonal plants that I have grown successfully within a mile of the coast include cabbage, peas, sunflowers, potatoes, Brussell sprouts, lettuces, Japanese pumpkin, scarlet runner beans, green onions and select varieties of tomatoes. So pick the plant winners for the coast! Unless you are in a very warm micro-climate, most of the warm season vegetables such as peppers, eggplants, melons, cucumbers, large heirloom tomatoes, etc. will be struggling in the chill summer.

Romaneseco head
Winter veggies like Romanesco grow well in cool summer climates

This is a must-have book for targeting plants that will grow on the cool foggy coast:

Golden Gate Gardening; The Complete Guide to Year-Round Food Gardening in the San Francisco Bay Area and Coastal California by Pam Pierce
Indie Bound Book Link