Success with Growing Eggplants

Row of Epic eggplants with flea beetle holes. Photo Pam Dawling.

We are about to transplant our eggplants, so I can tell you all about it. I’ll skip over the details of sowing, assuming you’ve already done that. After the growing info, I’ll summarize our variety trials in case you are considering which to grow next year. If you already grow more than one variety, I encourage you to track how each one does, to refine your future plans.

Eggplant Crop Requirements

Eggplants benefit from fertile, well-drained soils high in organic matter, with a pH of 6.0-7.0, with 6.0-6.5 ideal. Average moisture with plenty of warmth and sunshine are needed. Ideal daytime growing temperatures are 70-85°F (21-29°C).

Epic eggplant transplants. Photo Pam Dawling

Care of Young Eggplant Starts

You may have sown in plug flats or pots, or in open flats. You will probably have potted up the plants into 3-4” (7.6-10 cm) pots. We keep ours away from doors in the greenhouse in the cozy south-west corner. Protect the seedlings from flea beetles, as well as drafts, either in the greenhouse or on benches outside. Flea beetles cruise at low altitudes, so setting your flats 3’ (1 m) above the ground may be all you need to do to keep them away. Or you may need netting. Johnny’s Selected Seeds has 6.9’ x 328’ ProtekNet for $375. They say:

“ProtekNet netting keeps insects as small as flea beetles and thrips off tender crops while providing maximum ventilation to prevent heat stress on hot summer days. Fine synthetic knitted mesh is UV resistant and lasts 1–3 seasons. Easy to see through, so crops can be inspected without removal. For best results, use over Quick Hoops or Wire Support Hoops, bury the edges, and ensure foliage is not touching the net, so insects can’t lay eggs through it. 0.0138″ x 0.0138″ (0.35 mm x 0.35 mm) mesh. 89% light transmission; 62% porosity; Weight: 0.74 Oz. per sq.yd. NOTE: Cut netting longer than needed to accommodate shrinkage.”

 

Young eggplant under netting May 9. photo Pam Dawling

Gardeners Edge (AM Leonard) has 6.9’ x 32’ of the same mesh size for $58.94

The Dubois Agrinovation US website offers several nets with mesh small enough (0.0138″ x 0.0138″ /0.35 mm x 0.35 mm) to keep out flea beetles: 25g, 47g, 56g, and 70g. Some are more durable than others, naturally. 164ft rolls cost from $198.32. We have found ProtekNet to more durable than rowcover.

Transplanting Eggplant

Plant spacings of 18-24” (45-60 cm) in-row and 30-36” (76-91 cm) between rows are usually recommended – or more to accommodate machinery. We used to grow two staggered rows in our 4’ (1.2 m) wide beds, aiming to have the plants 30” (76 cm) apart. This created crowded aisles, so we now plant a single row in each bed, with in-row spacing of 20-24” (50-60 cm), creating a “hedge” and leaving the paths more accessible. This fits with the approach that considers the area each plant has, rather than the intensive planting approach that favors equal space in all directions.

To harden off for planting out, reduce moisture rather than dropping the temperature, as this crop is easily stunted by cold temperatures. Ideally, keep eggplants above 55°F (13°). Transplant the 8-12 week old plants 1-2 weeks after the last frost date, in a warm spell. The transplants should be 6-10” (15-25 cm) tall, without any buds, flowers or fruit. We leave our eggplants to be one of the later crops set out, after tomatoes and peppers. To help warm the soil, you could spread black plastic mulch two weeks before transplanting. This will also deter flea beetles. Avoid organic mulches at planting time, as they cool the soil. In cool climates, rowcover on hoops is a good idea for new transplants, to keep the plants warm. Fine mesh netting will keep flea beetles away.

Eggplant transplants with aphids.
Photo Pam Dawling

Our technique for minimizing flea beetles while transplanting is to set out hoops, and sticks to hold the netting down on either side of the bed. The rolled netting is at the ready. One or two people transplant, and a third person with a hose and spray-head gives the plants a strong spray, directing the flea beetles out of the bed. A fourth person follows close behind, unrolling the netting and battening it down quickly after each plant.

Caring for the Eggplant Crop

Once the soil is fully warm, you can cultivate and spread organic mulch. Because the plants will be in the ground for a long season, and organic mulches break down, we use our eggplant beds as convenient places to drop off finished crop residues or weeds – only healthy, non-seeding material of course. In hot dry weather, weeds can be pulled from the mulch and laid on top to die.

Any stress from cold weather, disease, or low fertility will cause eggplant skins to thicken and become bitter. If your soil fertility is low, feed monthly with fish emulsion, or side-dress with compost. Don’t overdo the nitrogen or you will get lots of leaves but few fruit.

We don’t usually stake ours, but if your area is windy, you could stake tall varieties, with 3-5’ (1-1.5 m) stakes every third plant around the perimeter and twine every 12” (30 cm) up the stakes to corral the bushes. Upright bushes may produce better shaped fruit. When the branches threaten to take over the aisles, snip them off as you harvest.

September jungle of eggplants and okra.
Photo Pam Dawling

Some growers pinch out the growing tips to encourage branching, although ours branch just fine without, and I hate removing bits of healthy crop plants. Conversely, growers in cooler climates sometimes prune low branches and leave just two main stems to be sure of getting some ripe fruit. In the fall, if rowcover is used to keep the first few frosts off, the big plants can ripen existing fruits. No new fruit will set once the temperature drops below 70°F (21°C).

As with most crops, the critical time for irrigation is during flowering and fruit formation. Insufficient water during this stage can lead to blossom end rot, misshapen fruit and reduced yield.

The above information is from my book Sustainable Market Farming. In the eggplant chapter you can find more about sowing, crop rotations, pests and diseases, harvesting, storage and seed saving

Eggplant Variety Trials

Nadia eggplant.
Photo by Nina Gentle

Most of my prior posts about eggplant have been about the years of variety trials we did from 2013 to 2016.

In December 2012, I wrote about trying new eggplant varieties

Back at the beginning of the 21st century, we had tried lots of different eggplant varieties, and found that Nadia consistently did best. After the hot summer in 2012 when our Nadia eggplant refused to set fruit in the heat, I started looking for heat-tolerant varieties. For a while in early summer 2012 the Nadia didn’t grow at all – no new flowers, never mind new fruit.  We chose large purple-black tear-drop shaped eggplant because that’s what our cooks want.

Listada de Gandia eggplant. Photo Raddysh Acorn

We didn’t include any green, striped, long skinny, orange, fluted or other unusual kinds. No judgment about people who like those! I looked at growing some combination of Nadia (67d, good set in cool conditions) with of

  • Epic F1 61-64d (early and huge!). Recommended in Florida and Texas.
  • Night Shadow F1 68d, (size claims vary from “similar to Epic” to “smaller.
  • Traviata F1 (variously recorded as 55-60d, 70d and 80d), small but good flavor. Recommended in Florida.
  • Irene F1 (mid-early). Large, shiny purple, traditional-shaped fruit 5″ x 6-7″. Great flavor, big plant, productive.
  • Classic F1 76d, heavy yields, high quality, does not perform well in cool conditions. Recommended in Florida and Texas.
  • Santana F1 80d, large, continuous setting. Recommended in Florida.
  • Florida High Bush OP 76-85d, reliable, large fruit, drought and disease resistant. Recommended in Florida and Texas.
  • Florida Market OP 80-85d, large, excellent for the South, not for the Northeast. Recommended in Florida and Texas.
Epic Eggplant
Photo by Nina Gentle

In 2013, alongside Nadia, we trialed: Florida Highbush, Epic and Traviata. Ironically, the summer of 2013 was not hot. One of the coolest we’ve had in a long time. We did a final harvest in preparation for our first frost, Sunday October 20/21, and I crunched the numbers. We planted 38 Nadia, 10 Florida Highbush, 10 Traviata and 12 Epic. Harvests started on July 25, later than our usual July 10, because of the cool weather. We harvested three times a week until 10/17. I was surprised how few fruit each plant provided – about 6. Initially, Nadia was providing by far the largest fruit, with Florida Highbush the smallest. Traviata doesn’t claim to be big. In the first week of harvests, Nadia produced most per plant, but this leveled off pretty soon. Final figures were 7.3 fruits/bush for Traviata, 6.3 for Florida Highbush, 6.1 for Nadia, and only 4.4 for Epic. We realized that we had stunted the Epic unintentionally by planting it at the stony end of the bed, near the road.

Florida Highbush OP eggplant
Photo by Nina Gentle

In 2014, we grew the same four varieties, to test them in a hot summer. But again it didn’t get hot! All four varieties have similar-sized fruit. We did better record-keeping, and found that the size and weight of each fruit was very similar across the varieties, varying only from Epic’s 0.61 lbs to Traviata’s 0.64 lbs per fruit average. Nadia yielded best per plant, at 13.4 fruits over the season. Epic was next at 12.5 fruits, then Traviata with 11.7 fruits. Florida Highbush was a poor fourth with an average of only 6.8 fruits per plant.

Florida Market OP eggplant
Photo by Nina Gentle

In 2015, we still did not get a hot summer! We had added a fifth variety for 2015: Florida Market, (like Florida Highbush, this is also open-pollinated.). By late august, Epic was winning, at 4.1 fruits and 3.4 pounds per plant, with an average of 0.84 pounds per fruit. Traviata was running second, at 3.1 fruits and 2.4 pounds per plant (average of 0.79 pounds per fruit). Nadia was third, at 2.3 fruits and 1.8 pounds per plant (average 0.75 pounds per eggplant). Florida Highbush (yes, it is a tall plant!) was beating Nadia on tonnage (2.1 pounds/plant) but losing on size (in other words, more, smaller eggplant). Florida Market was trailing, with many days providing no harvest. Our final figures for 2015 showed Florida Market’s fruits were smaller and rounder, and it had a lower yield. It was at the dry stony end (so unfair!) Epic did best, both in number of fruit/plant (10.7) and weight per fruit (0.77 lbs). Good thing we didn’t give up on it after 2013! Traviata provided 8.9 fruits/plant, Florida Highbush 8.2, Nadia only 8.0 (we did get a lot of culls too), and the Florida Market just 7.5.

Traviata eggplant with thumbnail dents!
Photo by Nina Gentle

In 2016,  we actually had some hot weather! We dropped the OPs and planted only the higher yielding Epic, Traviata, and Nadia. The September assessment showed of the three, Epic was winning! From the first harvest on 7/18, up to the end of August, Epic had produced a staggering 287 eggplants, averaging 0.9 pounds each; Nadia, 125 eggplants, averaging 0.76 pounds each; Traviata, 124 averaging 0.72 pounds. That year we also logged the cull rate: Nadia was best (least) at 21%; Epic was close at 22%, while Traviata produced a surprisingly high proportion of culls at 29%. During September, Traviata produced the largest number of saleable fruits (145) compared to 138 Nadia and 135 Epic. Probably not statistically different from each other. As I’ve noted before, the eggplants are all a similar size, and so it’s no surprise that Traviata’s 145 fruits totaled the highest weight (112.5 pounds), with Nadia at 98 pounds and Epic at 95.5. Nadia had an 8% cull rate, Traviata 9% and Epic only 6.8%. Clearly, all three are good varieties.

Adding September to the figures for August and July, Epic was the winning eggplant in terms of total yield, saleable yield, low cull ratio, and weight per fruit. That impressive leap off the starting blocks that Epic made was still holding it ahead of the pack. The ripe fruits got a little smaller, and there was been a noticeable drop-off in yield since the equinox.

Ping Tung Long eggplant. Photo by Southern Exposure Seed Exchange

After that, we grew Nadia and Epic, to cater for both types of summer. Recently some cooks developed an interest in Ping Tung Long, so we have been growing that as well as Epic.

2015 Eggplant Variety Trials

In the hot summer of 2012 we had trouble with our lovely tried and tested favorite eggplant (aubergine) variety, Nadia, setting fruit. That was disappointing, because we had tried lots of different eggplant varieties before settling on Nadia. The large purple-black teardrop or oval eggplant are what is popular here. Not the long thin ones, or the pale lavender ones, or the stripey ones. Nor the smaller open-pollinated ones. We found Nadia and loved it. Then we discovered its Achilles heel – it’s not good in hot summers.

Nadia eggplant. Photo by Nina Gentle
Nadia eggplant.
Photo by Nina Gentle

For three years we have trialed some eggplant varieties that we hope will give better yields in hot weather. We chose ones that claimed heat tolerance and were in our “large purple-black teardrop or oval” category. But ironically, we haven’t had hot summers since! I’ve got pretty good data on how the various varieties performed in OK summers.

Epic Eggplant Photo by Nina Gentle
Epic Eggplant
Photo by Nina Gentle

In 2013 we compared Nadia, Epic, Traviata and the open-pollinated Florida Highbush. We counted the harvested fruit but didn’t weigh them. Traviata gave 7.3 fruits/plant, Florida Highbush 6.3, Nadia 6.1 and Epic only 4.4. We noted that we’d planted the Epic at the dry stony end of the bed, in case that affected yields. As we found out the next year, it certainly did! We also had an impression that Florida Highbush had smaller fruit, but we weren’t sure.

Traviata eggplant Photo by Nina Gentle
Traviata eggplant
Photo by Nina Gentle

In 2014 we grew the same four varieties and this time we recorded the weight of each harvest as well as the number of fruit of each kind. This time we got better results overall: Nadia gave 13.4 fruits/plant, Epic 12.5, Traviata 11.7 and the Florida Highbush limped home at 6.8 fruits/plant. We failed to note which variety was at the dry stony end that year! We did find out that the size and weight of each fruit was very similar across the varieties, varying only from Epic’s 0.61 lbs to Traviata’s 0.64 lbs per fruit average.

Florida Market OP eggplant Photo by Nina Gentle
Florida Market OP eggplant
Photo by Nina Gentle

This year we tried the same four varieties and added another reputedly heat-tolerant open-pollinated kind, Florida Market. It’s fruits were smaller and rounder. The variety had a lower yield. It was at the dry stony end (so unfair!) Epic did best, both in number of fruit/plant (10.7) and weight per fruit (0.77 lbs). Good thing we didn’t give up on it after 2013! Traviata provided 8.9 fruits/plant, Florida Highbush 8.2, Nadia only 8.0 (we did get a lot of culls too), and the Florida Market just 7.5.

Florida Highbush OP eggplant Photo by Nina Gentle
Florida Highbush OP eggplant
Photo by Nina Gentle

Overall, it was a less bountiful year compared to 2014, at 812 fruits, 564 lbs – an average of 0.7 lbs each. A lot of eggplant! In 2014 we got more: 927 fruit, 582 lbs – an average of 0.63 lbs each.

What to do next year? Maybe just trial the three hybrids and not the Florida OPs. It would make life easier. Here’s our spreadsheet. I haven’t yet found a tidy way to copy Excel spreadsheets into a blogpost, so if someone knows how, please leave me a message.

2015 Eggplant Harvest Record number and weight of each of the five varieties. If none, write 0
  Nadia   Traviata   Epic   Florida Highbush Florida Market NOTES
# of plants 49 plants 17 plants 18 plants 9 plants 10 plants Record weight in pounds
Date Number Pounds Number Pounds Number Pounds Number Pounds Number Pounds  
18-Jul 1 1.2 0 0 3 1.5 4 1.5 0 0
29-Jul 18 22 13 13.5 16 18.5 2 3.5 0 0
1-Aug 1 2 0 0 0 0 0 0 0 0
5-Aug 6 5 3 3 10 10 1 1.5 0 0
8-Aug 31 17.5 14 9 14 10 4 1.5 2 1 Picked too small. Ave 0.4-0.7 lbs each. Goal 0.7-1.0 lbs
12-Aug 4 4 2 1 1 0.5 3 3 1 0.5
19-Aug 54 35 20 14.5 30 21.5 12 8 11 7 Picked a bit small.
26-Aug 20 12.5 10 8.5 23 21.5 5 4.5 13 9.5 Nadia many damaged
29-Aug 17 10 8 6 9 7 3 2 3 2
2-Sep 21 13 7 5 19 14.5 8 5 1 0.5 Nadia many damaged
5-Sep 22 15 10 8 10 7 4 2 5 3.5
9-Sep 18 11 1 2 8 5 2 1 6 3.5 Pl;us approx 1 lb over-ripe FL Mkt
12-Sep
16-Sep 30 20 28 16 0 0 18 11 7 4 Picked small. Epic maybe mixed with FL HB
19-Sep 21 15 0 0 18 13 0 0 5 3
23-Sep 41 28 13.5 8 13.5 8 1 0.2 10 5 Epic and Traviata confused, averaged
27-Sep
30-Sep 44 27.5 7 3 4 2 4 2.5 4 2
4-Oct
7-Oct 33 18 13 7 9 5 2 1 7 3
11-Oct 10 5 2 1 5 3 3 1
Totals 392 261.7 151.5 105.5 192.5 148 76 49.2 75 44.5 812
Per plant 8.0 5.3 8.9 6.2 10.7 8.2 8.4 5.5 7.5 4.5 564.4
Wt/fruit 0.67 0.70 0.77 0.65 0.59
Conclusions Epic did best this year, both in number of fruit/plant and weight per fruit. Last year it was second to Nadia in yield/plant, tops in weight/fruit. Florida Market had smaller fruit and a lower yield. In 2014 we didn’t grow FL Mkt; FL HB came fourth. Total yield 2015 was 812 fruits, 564 lbs. In 2014, we got 927, 582 lbs. Once again it was not a hot summer, so we didn’t find which does best in hot weather. Suggest we drop the FL OPs and just grow 3 vars next year.

 

Sweet potato harvest and eggplant varieties.

Bountiful sweet potato harvest Credit Twin Oaks Community
Bountiful sweet potato harvest
Credit Nina Gentle

Our sweet potato harvest is huge this year! We mostly managed to keep the deer out of the plot, by luck and a scarecrow and things that fluttered in the breeze. We’ve filled all our usual boxes and then scrambled twice to find more! There are about 20 plants we didn’t have time to dig up yesterday (our fourth harvest day). Hopefully we’ll get those out of the ground before the rain moves in. A big storm system is approaching from the south west. We’ve been lucky that we haven’t had any very cold weather since that first light frost on 10/5. I remember one awful year when we left the sweet potatoes in the ground too late, hoping they’d fatten up a bit to make up for a poor growing season. Instead, the weather got cold and wet, and the sweet potatoes were rotting in the ground (it was November by then), and those that didn’t rot got chilling damage that prevented them ever softening in cooking. Sweet potatoes that stay hard are no fun to eat! I wrote the harvesting details in an earlier post.

Boxes of sweet potatoes curing in our basement. Credit Twin Oaks Community
Boxes of Beauregard sweet potatoes curing in our basement.
Credit Nina Gentle

Anyway, back to this year’s good news – I counted the equivalent of 273 normal-sized boxes in the basement this morning. At 23 pounds for our standard box, that’s about 6280 pounds. We might be up to 6500 pounds by the time we’re done. This will be our record! I think our local food pantry will be getting some sweet potatoes this winter and next spring!

Last year I compared sweet potato yields for different years. We usually have about 600 plants in 800 row feet (16″ spacing). Yield is about 11 pounds/sweet potato plant this year. But as they say “your results may vary.”  Ours certainly have. Working back from 2012, we harvested 4070 lbs, 2208 lbs, 1860 lbs, “lots” (poor record-keeping!), 5590 lbs, 3820 lbs and 4050 lbs in 2007.


Nadia eggplant. Photo credit Kathryn Simmons
Nadia eggplant.
Photo credit Kathryn Simmons

This year we did variety trials of four eggplant varieties, to find one better than Nadia, which is a lovely variety, but didn’t do so well in the hot summer of 2012. Last year we ran the trial and we didn’t get a hot summer. So we tried again. Again, no hot summer! But we did good record-keeping! Here’s our table for this year:

Eggplant Harvest 2

What can we conclude? All four varieties have similar-sized fruit. We deliberately chose purple-black tear-drop shaped eggplant because that’s what our cooks want. We didn’t include any green, striped, long skinny, orange, fluted or other unusual kinds. No judgment about people who like those!

Traviata eggplant from Osborne Seeds
Traviata eggplant from Osborne Seeds

The four varieties, Nadia, Epic, Traviata and Florida Highbush (the only open-pollinated eggplant we included) all have similar-sized fruit, about 0.6 lbs each. Nadia yielded best per plant, at 13.4 fruits over the season. Epic was next at 12.5 fruits, then Traviata with 11.7 fruits. Any statisticians reading this? Are these numbers significantly different?

 

Florida Highbush eggplant from Seed Savers Exchange
Florida Highbush eggplant from Seed Savers Exchange

Florida Highbush was a poor fourth with an average of only 6.8 fruits per plant. Maybe we’ll drop that one from our experiments. On the other hand, with a name like that, perhaps it would do better than the others in a really hot summer!

Nadia eggplant from Johnnys Seeds
Nadia eggplant from Johnnys Seeds

The records are also helpful in seeing the flow of the harvest. We started harvesting 7/7. Nadia wasn’t ready. They peaked 8/6. We peaked 9/27 (“Almost over”!), after doing a drastic over-harvesting 9/24. We’re farmers not scientists!

 

 

 

Epic eggplant from Osborne Seeds
Epic eggplant from Osborne Seeds

On that theme, notice that one bed had thicker rowcover than the other, when transplanted. The two beds were next to each other. One was all Nadia, the other, the three contenders. The row cover could have skewed the results. Onward and upward! Maybe next year we’ll get some results we can bank on.