Interplanting in Tomatoes

A while back someone asked me some questions about the types of intercropping we have done on our farm over the years.  Apparently, we have developed a bit of a reputation for looking at ways to add diversity into our food crops - even while we try to grow efficiently for a commercial sales.

As with so many things on our farm over the years, change has happened... and we will no longer grow field tomatoes, moving them all to the high tunnels.  The reasons for that are threefold: 1. wet years have made field tomatoes difficult for us to grow, 2. herbicide drift have made field tomatoes difficult to grow, and 3. our demand has decreased.

But, that should not, and will not, prevent us from sharing what we have learned over the years on our farm.

The Layout of the Field

For several years in a row, the layout of our field followed a consistent theme.  One of our seven plots in the East, measuring roughly 200 feet by 60 feet.  We ran our rows the long direction (of course) in these plots to reduce turn-around time with our equipment.  This is more important with the tractor, but it still applies if you are using walk behind tractors and even wheel hoes.  The more time you spend turning, the less time you are actually doing the work!

Rows were five feet apart on center, which allowed us to run our tractor over these rows without infringing on the growing space.  This also gave us an easier time laying out drip tape for irrigation.  We also found that once trellising (usually cages) were in place there was still decent paths for walking and/or running a wheel hoe without much problem.  Remember - we're hoping to harvest lots of tomatoes and we need to be able to get them out of the field quickly and easily!

The picture above shows the field in the process of cultivation and in row weeding which tended to happen prior to the application of straw mulch under the tomato plants.  The row in the center is basil and we were just finishing wheel hoe passes on either side.  Yes, it had been wet so the weeds were bigger than we wanted.  But, it worked out fine.

Depending on the tomato type, our spacing was either 24, 30 or 36 inches.  Large varieties, such as Dr Wyche's Yellow tended to need the three foot spacing, while smaller varieties, such as Cosmonaut Volkov could be put closer.  But, in all cases, we preferred to provide a bit more space to allow for air circulation as we got later in the season.  Failure to do so could easily lead to powdery mildew and other problems.  Blight diseases also spread more easily with proximity.

What is in the Field?

Most years, we had twelve rows (or beds) in the plot:

• 1 row of larger flowers
• 2 rows of tomatoes
• 1 row of basil
• 2 rows of tomatoes
• 1 row of basil
• 2 rows of tomatoes
• 1 row of basil
• 1 row of tomatoes or eggplant or peppers
• 1 row of tall flowers

At our peak of tomato production, this field would hold somewhere from 400 to 500 tomato plants, 500 to 600 basil plants and lots of flowers.  We had a preference for heirloom and heritage seeds and usually had 20-30 different tomato varieties and as many as six basil varieties.  

A young Dark Opal Basil plant is shown above (about two weeks after transplant).  

We gave a significant part of the load to the Italian Heirloom variety and had blocks of 20 to 25 plants for other, important types such as German Pink, Nebraska Wedding, Black Krim, Wisconsin 55 and others.  To improve access, we left breaks in all of our rows at the 1/3 and 2/3 mark so we could walk into the center from the paths that separated each of our plots.

What does it look like when all is Right in the Plot?

The picture below shows me a field that I liked being in (at least until heavy fall rains made it less of all that!).  The zinnias are blooming on the right and the Dark Opal basil is of a size that harvests can be made.  The straw mulch is down to prevent soil splash on the tomatoes (which can spread disease) and the tomatoes are all caged.  

Each row has a line of drip tape under the mulch - including the flowers.  The only area that is not straw mulched is the area closest to the basil.

But, as you can see with the picture below, the straw has migrated closer to the basil plants over time, so it looks as if we had mulched them as well.  Between the mulch and the canopy in row, there won't be much problem from weeds in this field for the rest of the season.

You might be able to see our breaks at the 1/3 mark in these pictures (sort of).  And if you look carefully, you'll notice the basil variety changes at that point. 

Over time, we invested in the square, collapsible cages (some 3 foot height, some 4 foot height) and do not regret that addition.  We found the stake and weave trellising method did not fit our available labor and we prefer to let the tomatoes spread out naturally with the cage reining them in.  As with any trellising method, there were periodic 'training sessions' required to remind the plants that we would like them to restrain themselves at least a little.

There's Always More to it!

As I worked on this post, I began to realize that there are many, MANY additional things I could add about how we did things with this planting.  For example, some years I would use a single point chisel plow to break the center of each row open where we would plant the tomatoes.  

Nearly every year we did not have enough demand for basil to justify all of the plants we put in - but that was ok because we wanted sections of it to bloom for habitat purposes.  If you like this layout, pick sections that will be maintained for harvest and sections that will be allowed to be habitat. You won't regret it. 

We selected tall flowers because we wanted them to help provide additional leaf cover later in the year for some  of our smaller heirlooms that didn't have a great canopy.  This was a natural way to reduce sun scald on some of the fruit.  We often would choose taller varieties with strong leaf cover to be south of another variety that did not for the same reason.

Sometimes we would throw flowers into rows to mark the change from one variety to the other and we almost always had flowers on the ends of the rows.  We even looked into planting basil in between tomatoes in their row (not a good idea) and we wanted to consider alyssum in the same capacity.

More Variations on a Theme

Over time, we came to the realization that spreading straw mulch was a time sync that our labor situation was not handling well.  The combination of initial pruning, cultivation, mulching and caging simply took to long.  Thus, we moved to using paper mulch in the tomato rows with good success.  While paper mulch may cost money, it cost less than the labor and we dealt with a bottleneck that caused us problems every year.  When all was said and done, we saved money (we had to buy in the straw).  But, it is also true that we weren't adding as much organic matter to our soils - but that's what cover crops and compost are for!

Speaking of which, we did try to put in a Dutch White Clover in between the paper rows one year, but the weather did not cooperate, failing to rain to aid in the cover's germination.  Well, that was true until September - then it rained like nobody's business!  It drowned the tomato and basil crops, but the clover started germinating just fine once the puddles when away - alas!  I suspect if we established the clover in the paths earlier it might have worked out pretty well.  My only concern would be having to trim non-clover weeds in the row.  But, we never did get to that point in our experimentation.

Now that we've reduced the number of tomato plants we will grow (and the number of varieties) we will move them all inside our high tunnels.  We can control the amount of water they get (for the most part, unless the water table rises like it has some years) and we can provide some protection from herbicide drift.  

Actually, there were several years where we grew the outdoor plot AND a couple rows of tomatoes in the high tunnels.  So, we have had some experience with interplanting inside as well.

We refuse to grow only one crop in a high tunnel because we believe deliberately choosing to promote a 'controlled diversity' inside the building will help us with pests and diseases over the long run.  The picture at the right shows our two tomato rows in Eden (our smaller high tunnel) with the walking path between.

The tomatoes are stake and weave trellised and there are sweet alyssum growing at the base of the plants. I don't recall, but there may be some marigolds on the ends.  

Earlier in the season, the north sides of the tomato rows were the home of lettuce plants that enjoyed the shade the tomatoes provided until we rudely cut them off at the base and gave them to customers!  Other adjacent beds had crops such as carrots and beets or green beans.

I wonder how we'll do things in 2021.  I can tell you one thing is certain, there will be some sort of intercropping with the tomatoes.

Have a good day and I hope you got an idea or two for your own growing!