Intensive, Raised Bed, Companion Gardening

by Brad Sylvester

When we moved to our new house in the winter of 2007, we knew it would be a challenge to grow as many vegetables as we wanted.  Although we have a little over five acres of land, at least 4 acres is wooded and we want it to stay that way.  The remainder is split between the house, driveway and open area.  the open area has steep hilly sections and a generally poor soil quality.  Our eventual goal was (and still is) to grow all of our own vegetables (excluding wheat and other grains since there is no real substitute for lots of land for these).  So we started researching ways to grow more in less space and ways to overcome poor soil quality. To complicate things, we wanted to achieve this goal without spending a fortune. 

We looked at hydroponics (if you get the chance to take the Behind the Scenes Tour through the experimental gardens at Disney's Epcot Center, I highly recommend it. Among other wonders, they have a single tomato plant that has produced over TEN THOUSAND pounds of tomatoes in about 18 months), but aside from being expensive, hydroponics seemed like a high risk option.  The chance of catastrophic failure of the system resulting in a complete loss of the crop or possible damage to the house from overflow seemed too high.  (Although we are experimenting with smaller home-made systems- we'll get around to writing about it soon...)

We then looked at Square Foot Gardening.  This seemed to hold more promise, particularly when combined with raised bed gardening.  The raised beds would help with the poor soil conditions as well as lower maintentance time, while the square foot gardening would increase the yield for the limited area we could devote to the gardens.  We went a step further and added Companion Planting to the mix as well.  For those not familiar with these methods, we'll give an overview of each and talk more specifically about what we did.  First off, never being one to stay inside the lines, I couldn't restrict myself to planting each crop in rigidly marked squares of 12" by 12".  So although similar in philosophy, we're not really Square Foot Gardening, but are practicing a technique more like "French Intensive Gardening," though we deviate from this a bit too.

Companion Gardening

First off, let's talk about Companion Gardening.  Put very simply, Companion Gardening is the practice of planting together two or more dissimilar plants that provide some synergistic benefit by being near one another.  The most well-known example of companion planting was termed the "Three Sisters" by the Native Americans.  This was the co-planting of corn, squash,  and beans.  The corn acted as bean-poles for the bean plants to climb. Beans are excellent nitrogen-fixers (adding nitrogen to the soil to be used by the other plants). The squash acted as a sort of ground cover, preventing weeds from receiving sunlight enough to grow and outcompete the planted crops.  So when planted together, the combined yield of the three was greater than if the three crops had been planted separately over the same amount of land.  There are many plants that offer or receive real benefits from companion planting (and many more that are rumoured).  There are even plants that will harm each other if planted near one another in a sort of reverse companion relationship.  Fennel, for example, is said to stunt growth or outright kill many other garden plants if planted too closely.  It is thought that they do this through some sort of allelopathy (a chemical defense system) that helps protect the fennel plant from being crowded out by weeds.  This doesn't mean that you shouldn't plant fennel. Not only is it delicious, but it is also a favorite haunt of beneficial ladybugs.  Our page on Aphids gives another example of companion planting that we've used with good success.  Rather than go through the whole list of what can and can't be planted with what in the middle of this article, we'll post a separate page with a much fuller listing of companion plants - when we get around to it ;-) .  Meanwhile, you get the basic idea.

Raised Bed Gardening

Raised Bed Gardening can be done with or without frames.  The basic idea is that the area in which you plant is heaped up higher than the surrounding ground level.  It is typically done in rows narrow enough to reach the center without ever walking in or on the planted areas.  This helps to minimize soil compaction.  Soil compaction is when the soil is compressed and becomes hard and dense, making it difficult for young plant roots to grow and thrive.  Additionally, raised bed gardening means that the soil in the planted area can be more easily treated by the addition of compost and other organic material.  This helps keep the soil quality very high and full of essential nutrients.  The soil in the raised beds will typically heat up more quickly, aiding plant growth.  With respect to watering, raised bed gardens are both a positive and negative.  On the one hand, you only need to water the area that is actually planted.  The in-between areas where you walk don't get watered as they would in a typical garden.  On the other hand, raised beds can tend to dry out faster than typcial gardens because they have more surface area exposed and they are a little warmer.  Most folks build frames to hold the dirt in their raised beds.  These frames can be made of almost anything so long as it is non-toxic.  Cement or cement-blocks, however, will leech water out of the soil very quickly meaning you'll have to water it far more frequently. 

We started off with four raised bed gardens, each one 12 feet long by three feet wide (including the frame).  We built them out of 2" x 12" x 12' pressure treated lumber. Contrary to the popular notion, reliable studies show that arsenic or other harmful chemicals do NOT leech out of modern pressure treated wood and into the garden soil.  (creosote-treated railroad ties are a different story.  Don't use them!) We made each bed three feet wide and twelve feet long. We simply cut the end pieces to length and used galvanized nails to secure them. We placed them directly on top of our existing lawn and filled them with new topsoil. As we filled them, we mixed in peat and composted manure to provide some organic material for the first year. In subsequent years, we'll add our own, fresh-brewed compost.  This picture shows the first one we finished. You can see some of our plantings in the photo. We'll add more beds each year until we can supply our entire year's vegetable needs.  Because our raised beds are 12" deep, we did not dig down below ground level.  However, if you use a shallower bed, say 6" deep, it is advisable to dig the soil beneath the raised bed and till compost and peat in before adding your new soil over the top.  Many vegetable roots will reach more than 6" deep. 

Click the thumbnail for a larger image

Intensive Gardening

To oversimplify, Intensive Gardening, or Square Foot Gardening, is the practice of planting things too close together.  It is done almost exclusively with raised beds of one type or another.  Since the beds are narrow enough to reach across, there is no need to use the row spacing requirements recommended for each plant.  In other words, a typical seed packet might say something like:  plants should be spaced 4" apart in rows 15 inches apart.  In this example, we would ignore the 15" spacing and plant in a grid with 4" between plants in each direction.  This gives the plants enough room to grow, and we don't need rows due to the narrow raised bed, we still have room to tend each plant.  Additionally, the tightly packed plants help to shade the ground and crowd out unwanted weeds.  Some people will use a heavy mulch in their raised bed to further suppress weeds and to help retain moisture in the soil.  This can substantially reduce the maintenance required for the garden, and as the mulch breaks down, it adds nutrients to the soil.  We chose not to use mulch in our raised beds, because we wanted to make sure to keep our plants disease free.  If a mulch stays too moist it can be a breeding ground for fungus and can also provide a home to harmful insects.  When using closely crowded plantings, you need to make sure that you don't space plants so closely together that there isn't good airflow between and amongst the plants.  Poor airflow can increase the risk and severity of plant diseases such as tomato blight, powdery mildew, and others.  You should also take care not to work among the plants when they are wet.  Some diseases can be more easily spread when the plants are wet (particularly bean plants- never harvest or disturb the beans when they're wet).     Intensive gardening also makes use of Succession Planting.  This is just planting one crop immediately after another is harvested instead of allowing the space to remain unused for the remainder of the season.  So we might harvest beets in July and immediately plant another short-season crop such as beans or peas which will have enough time to mature before the hard frost comes in to end the season.  Another option would be to plant something that can over-winter in the ground like some leeks, shallots, or even carrots (depending upon where you live - we have successfully overwintered all of these in Connecticut). 

Email us with any comments or suggestions about what you like to see here

The words and photos found on this website are copyrighted (2007, 2008) with all rights reserved and may not be reproduced in any fashion without our express written permission. However, we will be liberal in granting that permission if you ask nicely, include acknowledgement of the source, and a link back to our website. The photos are our original property, if you’d like to use them for your own project, you must contact us for permission. They are also available in high resolution.  Contact Us.