The All American Tomato Trial

how to grow heirloom tomatoes

Sadly dear readers, the above tomatoes are not of my growing.   They are fresh from the inspiring Instagram feed of @grow_fish_cook who, along with all other American gardeners, has been in the thick of his tomato harvest in recent weeks.   His garden in Manassas, just outside Washington, is the scene of some serious tomato growing that has had me drooling and dreaming of our coming growing season.

My tomatoes started life two weeks ago and are just getting their first leaves coming through.   This season I’ve been inspired to grow some of America’s favourite heirloom varieties by the displays from @grow_fish_cook and also by an excellent magazine I got for my birthday called Heirloom Gardener.   Their fascinating story “12 All-Time Tomato Favorites”,  in the summer 2013 issue, canvassed opinion from Americas leading seed savers and tomatophiles on their most treasured varieties and summarised the history, flavour and character of each.

growing heirloom tomatoes

We’ve sourced and added a selection of these varieties to our heirloom tomato seed collection.   Choosing was hard but I’ve limited myself to growing 5 varieties from their top 12.   I’m a sucker for a good back story, so I had to grow Mortgage Lifter. Apparently, the man who bred it, paid off his mortgage selling the plants to gardeners in depression era America.   I’ve also heard from local customers that it is a reliable cropper with strong plants and a less acidic flavor than Beefsteak.   The article notes that it has been honored into the Slow Foods “Ark of Taste”.

I also had to give Aunt Ruby’s German Green a grow because true green tomatoes, that are green when they are ripe, are really underrated.   I’ve grown Green Zebra before and found the flavor almost like walnuts and very rich. Auny Ruby’s German Green also has a robust flavor that is sweet, spicy and delicious.    She has been a bit slow out of the blocks though.

The “black” varieties always rate highly in the flavor stakes, so no surprises that 4 out of the top 12 in the Heirloom Gardener article were black or purple skinned.   I’ve chosen Black Krim, Paul Robeson, and Cherokee Purple to complete my top 5.

Grow Black Krim Tomatoes

The one slight problem I face in attempting to grow these new varieties is that I have psyllids, (not something you really want to say in company but there you go I have), and so for the past three seasons I haven’t been able to grow a decent crop, or any crop of tomatoes at all!

Psyllids are a relatively new pest to New Zealand gardens, they are awful little sucky bugs that live to annihilate all members of the nightshade family which include toms, spuds, chillies and peppers.  They breed like rabbits and decimate all but the fastest, earliest varieties.  I don’t like spraying my veges with chemicals, and so try as I might, I’ve only managed enough for a tomato or two on toast.   I’ve had to BUY tomatoes for pasta sauce, tomato soup and relish. It has been a bit tragic. But this year I’ve planned an experiment to try and beat the little suckers.

I am buying in some fresh soil and growing my tomatoes in tubs, well away from the main garden. One set is going to be sprayed with full on chemical control sprays every 7 days, one set is going to be sprayed with organic controls and the third set is going to be left to fend for itself. The aims are to get a crop even if it isn’t spray-free and hopefully to learn what works to control pysllilds so we can share it with other gardeners.

Anyone who has battled the psyllid bug and has any words of wisdom is welcome to comment. I have another few weeks of tender loving care before my wee toms will be big enough to plant out.

This post will be updated during the summer so please check back in to see how the great American Tomato Trial is working out!

Update One:   1 Month

Well we made it through the first four weeks inside on the heat pad and today I pricked out the little seedlings into biodegradable pots.   Here are a few tips and tricks for pricking out seedlings.

growing heirloom tomatoes

  • Put your potting mix through a soil sieve to get rid of the big twigs and lumps that will slow down little seedling roots and mix it 50/50 with some seed raising soil to make it more free draining.
  • Fill pots approximately 3 inches wide and poke a hole in each with a dibber
  • Use an old fork to gently lift seedlings, holding them by the first cotyledon leaves, not the stalk or the second leaves.
  • Lower them into the pots so that at least half of the stalk of the seedling is buried in the soil.  Roots will grow along the stalk and burying it deeply makes for strong plants.
  • Water lightly, avoiding wetting leaves.
  • Keep potted seedlings indoors on a heat pad or in a warm place until the soil temperature outside reaches 10°C – 12°C overnight outdoors.

how to prick out tomato seedlings


Update 2 Months

The seedlings have been progressing well inside.  It didn’t feel like it but looking at the photos from 4 weeks ago they have indeed grown.  They were getting a little spindly looking so I asked Miles from Garden Organics about the key to getting lovely robust plants.   You could make a tree hut in their tomato seedlings they are so sturdy!

He shared with me that they foliar feed their tomato seedlings with a liquid seaweed and comfrey based fertiliser. I’d always thought spraying water on tomato leaves was a recipe for all manner of fungal disease and blight but he assured me that if you do it first thing in the morning it has time to air and dry and makes the world of difference to the growth.   He also waters the soil with the same mixture.

So a couple of weeks ago I invested in a bottle and have seen a marked difference in the strength of the plants.   The night temperatures are still too cool for the plants to be outdoors so I’ve had them on a heat pad on the kitchen windowsill.  The plants closest to the glass are noticeably smaller which shows you the impact the cold night temperature coming through the window has on growth.

Now they’re at 2 months old I’m “hardening off” the seedlings by putting them outside for a couple of hours a day in the shelter of my front porch.   Just to get them used to the idea of leaving their cushy heat pad and avoid transplant shock which can slow down growth or kill the plants.

This will give me time to start getting the planting soil ready and hopefully give these spring winds a chance to drop off before I plant.

hardening off tomato plants

To see the progress of our trial tomatoes in during the rest of the summer click here.



  1. Have you tried putting neem granules in the planting hole for your tomatoes? The plant takes up the active ingredient so the psyllid doesn’t get a hold – neem inhibits the breeding cycle of insects.

    1. Thanks for that Leah, I’m going to try Neem granules. Have you tried it?

  2. I second the neem granules. I put them in the planting hole of tomatoes and potatoes and so far haven’t had any problems. I do add a second dose around the base of the plant about halfway through the season, just to be on the safe side.

    1. That’s great, thanks Annmarie. I am definitely going to give that a try now and top them up half way through the season.

  3. A number of people recommend a combination of Neem granules and Neem oil. Being lazy, I’m hoping the Neem granules will be sufficient.

    1. Jim, we’d be really interested to hear how you get on with just Neem granules. Let us know the results. Anything that means less work in the garden has to be good.

  4. What wascthe name of the seaweed fertiliser please

    1. Hi Sue, it is Garden Organic’s own brew that they sell at the Saturday market in Nelson.

  5. Neem granules are great, the improve plant health and fight more nasties that just psyllids. If you really want to deal to the psyllids, I highly recommend ‘Psyllid Solution’ from Koanga Gardens It’s non toxic, organic and works mechanically on the exoskeleton of the psyllids, so no poisons involved. If only it destroyed blight too!

    1. Hi Sarah, thank you for that – sounds great. I will give it a try for sure.

  6. Last year I planted some tomatoes in my garden and some in Earthboxes (wicking containers) on my deck – which goes from ground level to one story high (ie, built on sharply sloping section). Tomato varieties were the same in each site. The garden grown tomatoes were badly infested with psyllids with the fruit being inedible. Although some psyllids found my container grown tomatoes on the deck – they were way fewer than in the garden and I was able to harvest beautiful tomatoes. I checked for psyllids daily and squished any I found. Just too many on the garden grown tomatoes to make this possible.

    I had read that psyllids can be partially prevented by surrounding the plants with a barrier as they dont fly high. So I figured my deck might inhibit their attack in the same way which seemed to work. Or perhaps the separation from the main garden helped too.
    This year I”m only growing my tomatoes on the deck. But will sprinkle some neem granules onto the soil also. Hopefully I’ll get good tomatoes again this year.

    1. Interesting Annie, thanks for sharing. I think you may be onto something with the height thing as my toms planted in high barrels are so far (fingers crossed) doing really well. Also the ones with Neem Granules are doing super well. Neem oil not so well. Interesting that you could see the psyllids to squish them. I keep trying to catch them in the act but I can’t see them. I can see where they’ve been with curled up leaves and sugary sap but I can’t actually see them.

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