Notes & Dates/ Crop Rotation/ Growing Potatoes

February 9, 2018

We and the bees have been busy in the gardens. I took a moment yesterday to appreciate the flowering quince in our herb garden -full of gorgeous red flowers and abuzz with native bumblebees. 

Taylor has been working hard on clearing out the lower garden, potting up the herbs, and planning irrigation and terraces to make the space more inviting for gardener and pollinator alike. Perhaps you'll check it out during our upcoming garden resource day- tomorrow, 2/10 from 10am-1pm. Taylor will be working in the herb garden in the afternoon tomorrow in case you are inspired to come help out!

We've spent time in a few of the neighborhood gardens facilitating path maintenance and mulching- when we have these warm, dry winters it feels like everything needs to happen NOW and it gets a little overwhelming. But we'll keep plugging away at maintaining our community garden spaces around the Presidio and look forward to each of you doing your part to weed your paths and beds. We're keeping busy tending beds we use for PresidioGrown, too! Lettuce, arugula, potatoes, leeks, onions, carrots, radishes, and peas are all in the ground.

Hayley, one of the Trust's Landscape Gardeners, came to the garden last Thursday to teach us how to prune our roses. We left one bud that has already opened...

And these women from Taylor's Garden for the Environment class have been spending their 40 hours of volunteer time with us. They are a huge help and lots of fun!

Upcoming garden dates:

2/10, Ft. Scott 10-1pm 

Garden Resource Day: compost and a few seedlings available at the garden

Abby helping wash pots

Volunteering in the Garden: help maintain our signature garden site

2/10, Ft. Scott 2-4pm 

2/15 and every Thursday through April, 10am-4pm

Evening garden visits start on 3/20

March 22: Spring Equinox Pizza Potluck, 4-7pm RSVP here

April 17: Spring Planting Deadline (don't wait- there's plenty you can plant now to take advantage of the warm weather!)

Blog Post #8: Crop Rotation

Hey community gardeners! I hope that you all are spending some time this month reflecting on your raised beds and creating planting plans for the next few months. Reflection and planning time is essential to your continued success in the garden. A question to ask yourself that may help in establishing a planting plan is, “what have I grown in my bed in the past year(s)?” Repeatedly growing the same vegetables in your bed year after year, season after season can cause a buildup of pests and diseases. Planning for crop rotation is a dynamic way to avoid this buildup while also making better use of soil nutrients.

When rotating crops, gardeners must look at the different ways to categorize crops in order to make a plan. Some rotate crops based on whether the plant is a heavy or light soil feeder and some rotate by botanical plant families. Neither of these methods are wrong, and a combination of both would probably be the most effective way of rotating crops. I’m going to outline and analyze both methods below to help you all start planning for the year ahead!

(1)    Heavy, neutral, or light soil feeders

Some crops use a larger amount of soil nutrients than others, these crops are called heavy feeders (cucumbers, lettuce, squash, tomatoes). At the opposite end of the spectrum are light feeders. Light feeders use only a small amount of soil nutrients (carrots, onions, chard, potatoes) and have less of an impact on the soil in your raised bed. Neutral feeders have virtually zero impact on soil and can even be turned back into your raised bed to increase nitrogen levels (fava beans, snap beans, peas). A good practice with rotating feeders is to follow heavy feeders with light or neutral feeders and vice versa. So if you planted tomato plants over the summer, you might want to think about planting a light (chard) or neutral (peas) feeder in order to give your bed some time to recover and build up its nutrients. Similarly, follow light or neutral feeders with heavy feeders. This is a great practice and will keep your soil happy and healthy!

(2)    Botanical plant families

It’s important to know that crops in the same botanical plant family are subject to the same pests and diseases. So, when planning your rotation, make sure you are not putting a member of the same crop family into a less than desirable location. Ideally, wait three to five years before growing the same vegetable, or a closely related one, in the same location. For example, root maggots are a serious pest to those growing carrots and parsnips (both crops are members of the carrot family- Apiaceae). If you were to plant carrots one year and parsnips the following year in the same exact spot, odds are that root maggots would end up doing a good amount of damage to your parsnip crop.

I am including a table (from Golden Gate Gardening by Pam Peirce) in this post that will hopefully help you to synthesize these two crop rotation methods. It outlines whether the plant is a heavy, light, or neutral feeder and also lists the botanical plant family that it belongs to.

Thanks for reading! Email me if you have any questions or need some advice with plant planning. tjais@presidiotrust.gov

-Taylor

Heavy Feeders
CROP	FAMILY
Basil	Mint
Beet	Amaranth
Celery	Carrot
Cole crops	Mustard
Corn	Grass
Cucumber	Gourd
Endive and chicory	Aster
Lettuce	Aster
Parsley	Carrot
Spinach	Amaranth
Squash	Gourd
Tomato	Nightshade
Light Feeders
CROP	FAMILY
Carrot	Carrot
Leek	Amaryllis
Mustard	Mustard
Onion	Amaryllis
Parsnip	Carrot
Pepper	Nightshade
Potato	Nightshade
Shallot	Amaryllis
Swiss Chard	Amaranth
Turnip	Mustard
Soil Neutrals
CROP	FAMILY
Fava Bean	Legume
Lima Bean	Legume
Scarlet-Runner Bean	Legume
Snap Bean	Legume
Pea	Legume
Soy bean	Legume

Finally, for those of you interested in growing potatoes, click to read more about how to do that:

You want to purchase certified disease free potato sets, like these we bought at Green Jeans in Mill Valley: irisheyesgardenseeds

 The best way to get the biggest yield is to dig down as far as you can in your garden box. Potatoes only grow above the seed potato you plant. This can be tricky in your raised garden bed as you'll need to pile the soil somewhere else in your bed.

 Then lay the potatoes at the bottom of the trench/hole you dug and just cover them with soil, enough so you can't see them but no more. Don't water until you see green leaves. 

As the plants start to grow, you'll add soil to the trench from that pile you made. When the vine is about 8" tall, cover half the stem of the plant and any associated leaves. Do this several times as the plant grows and it will make potatoes off the stem into the nice fluffy soil. Don't wait until the plant is too tall! This is a gradual process to produce the best yields. In about 3 months when the leaves start to yellow OR 2 weeks after they flower, you can harvest your new potatoes. Digging for potatoes is one of the most rewarding gardening tasks- enjoy!