Somewhat optimal order in which to gather the seeds:

1. baker's wheat
2. meddleweed
3. thumbcorn
4. Brown Mold
5. Chocoroot
6. White Mildew
7. Crumbspore
8. White Chocoroot
9. Glovemorel
10. Wrinklegill
11. Bakeberry
12. Doughshroom
13. Shriekbulb
14. Cronerice
15. Wardlichen
16. Tidygrass
17. Gildmillet
18. Queenbeet
19. Golden Clover
20. Ordinary Clover
21. Green Rot
22. Shimmerlily
23. Keenmoss
24. Cheapcap
25. Fool's Bolette
26. Whiskerbloom
27. Chimerose
28. Nursetulip
29. Elderwort
30. Ichorpuff
31. Drowsyfern
32. Duketater
33. Everdaisy
34. Juicy Queenbeet

(with savescumming)

This assumes that you are extremely familiar with how the garden ticks work and are comfortable savescumming to advance the garden as fast as
possible.

If you'd like a bit more in-depth as to how to achieve this unlock order, my strategy is roughly as follows (with a level 9 garden obviously):

-Begin (1 seed) with Fertilizer and plant 5 Baker's Wheats in the second row from the top, leaving one of the middle plots in the row empty.
-Savescum the first tick until you spawn a Meddleweed on the south portion of the garden.
-Repeat this with the 2nd and 3rd tick to spawn 2 more Meddleweeds, ensuring that at least two of the Meddleweeds share at least an empty plot around them
(this is for doughshroom).
-When the Baker's Wheats mature, you will likely get a Thumbcorn mutation; at this point swap to woodchips and scum a Bakeberry on the next tick.
-By this point your first Meddleweed should be mature, scum-harvest this mature Meddleweed (2 seeds) until it produces either a Crumbspore or a Brown Mold
(if it's one of the two Meddleweeds that share an adjacent plot, then it must produce a Crumbspore, otherwise it must produce a Brown Mold).
-Repeat this process with the non-mature Meddleweeds, until you have 2 Crumspores close to each other and a brown mold growing. Make sure to swap back
to fertilizer asap.
-Wait until the thumbcorn matures and scum a Cronerice. Once you scum the cronerice collect the Thumbcorn seed (3 seeds)

At this point you can get rid of the excess Baker's Wheats. You will probably unlock the next plants in roughly the following order (make sure to get all
of a plant's available mutations at that time before harvesting it, except where noted):

-Chocoroot (plant a baker's wheat close to your brown mold which doesn't have to be mature; or use an existing baker's wheat if you got lucky with the
position of the plot where your brown mold spawned)
-White Mildew (spawns from the brown mold once it's mature). Hopefully it spawns close to your chocoroot.
At this point you harvest the brown mold (4 seeds) and plant a new one close to one of your crumbspores when it has ~5 ticks left to mature.
You can also plant a thumbcorn close to a crumbspore at this point.
-White Chocoroot (from your chocoroot and white mildew). Once your white chocoroot spawns you can safely harvest the chocoroot for its seed (5 seeds).
-Plant a Baker's Wheat next to your white chocoroot.
-Soon your white mildew will mature and you can harvest it (6 seeds).

At this point your crumbspores will mature. From them you can spawn the following 3 plants:
-Wrinklegill (Crumbspore+Brown Mold)
-Glovemorel (Crumbspore+Thumbcorn)
-Doughshroom (2x Crumbspore, use wood chips for this one)
Once the 3 plants are spawned, collect the crumbspore seeds (7 seeds) and clean up the thumbcorn/brown mold.

Once your white chocoroot matures, scum a Tidygrass using Wood Chips and then harvest the white chocoroot (8 seeds).

At this point you have the 6 following plants growing in your garden:
Bakeberry, Cronerice, Wrinklegill, Glovemorel, Doughshroom, Tidygrass.

Soon your bakeberry will have <23 ticks left to mature. When this is the case, plant a chocoroot next to it in preparation to spawn a Queenbeet.
-Harvest your glovemorel once it's mature (9 seeds).
-Harvest your wrinklegill once it's mature (10 seeds) and immediately plant it next to your cronerice (which should have roughly 25-35 ticks left to mature).
-If the cronerice has more ticks left to mature, wait until it has <35 ticks then plant the wrinklegill next to it.

-When your bakeberry matures, scum a queenbeet immediately and then harvest the bakeberry (11 seeds).
-Harvest your doughshroom once it's mature (12 seeds) and plant as many as you can in 2 separate, non-subsequent rows (leaving as many empty plots with
4 doughshroom surrounding the plot as possible). Use this to scum a shriekbulb (with wood chips if you like - it doesn't require the doughshrooms to
be mature) and then uproot the non-mature Doughshrooms immediately.
-Finally your cronerice will be close to maturing, when it has ~5 ticks left to mature plant a white mildew close to it, and when it has ~4 ticks left
plant a thumbcorn)
-Around this time your shriekbulb should mature, harvest it immediately (13 seeds)
-Once your cronerice matures the first thing you will scum is an elderwort using wood chips. This might take close to a hundred tries or more. Try to
have the Elderwort spawn in the upper 3 rows of the garden if possible (your lower rows should be mostly free except possibly for the tidygrass/shriekbulb)
-Once your elderwort spawns you can scum a wardlichen and a gildmillet (in that order).

Once you've spawned these 3 plants you can harvest your cronerice (14 seeds) and swap back to fertilizer. Clean up the excess plants.

-Plant a Baker's Wheat next to your gildmillet once it has 9 ticks or less left to mature)
-Harvest your wardlichen once it's mature (15 seeds)
-Around this time your tidygrass might also mature, harvest it immediately (16 seeds).
-When your Gildmillet is mature, hopefully you planted a Baker's Wheat next to it giving you 4 eligible spots to spawn clovers.
-Swap to Woodchips and scum a Golden Clover. This has around 0.8% chance to spawn with 4 eligible empty plots and will take you roughly 125 or more tries.
-Once you've scummed a Golden Clover, spawn an Ordinary Clover if you didn't already get one on the same tick as the golden clover.
-Harvest your Gildmillet (17 seeds) and the Baker's Wheat. Immediately plant a Gildmillet right next to the Ordinary Clover.
-Also plant a Doughshroom in either the upper left or upper right corner of your garden, whichever is less cluttered (this is in preparation for
fool's bolette).

Before this or soon after, your Queenbeet should mature, immediately harvest it (18 seeds) and plant two rings of Queenbeets on the lower half of your
garden, giving you 2 eligible spots for JQB.

-Harvest your golden clover immediately once it matures (19 seeds).
-When your ordinary clover has 5 ticks left to mature, plant a white mildew close to it; also plant a crumbspore close to the spot where you plan to spawn a
shimmerlily. (It can be hard to manage space at this point, but even having one possible spawn plot for mutations suffices because the chances are high).
-Once your ordinary clover matures (hopefully at the same time as the white mildew), spawn a green root and immediately plant a brown mold next to the green
rot. You will have to manipulate the ticks a bit in order to have the green rot and brown mold mature at the same time.
-Spawn a Shimmerlily as well. Once it begins to grow, harvest the ordinary clover (20 seeds) and the gildmillet. Plant a White Chocoroot close to the
Shimmerlily (leave 2 empty plots adjacent to both the white chocoroot and the shimmerlily).
-Once you manage to make both the Green Rot and Brown Mold mature at the same time, use them to spawn a Keenmoss and immediately harvest the green rot (21
seeds) and the brown mold. Plant a chocoroot next to the Keenmoss.
After about 6-10 ticks, your doughshroom should have 4 ticks left to mature. Exactly at this point plant a green rot close to it.
-Once your shimmerlily matures, use the following 3 ticks to spawn: 1 Cheapcap and 2 Whiskerblooms. Use Wood Chips if necessary.
-Once you manage to make these 3 plants to spawn, harvest the Shimmerlily (22 seeds), clean up the crumbspore and white chocoroot.
-Around this time your Keenmoss should mature, use wood chips to scum a Drowsyfern seed and harvest the Keenmoss (23 seeds)
-Once the doughshroom and green rot mature, spawn a Fool's Bolette. Clean up the Green Rot and Doughshroom.
-Once the cheapcap matures, immediately harvest it (24 seeds)
-The fool's bolette will mature, harvest it immediately (25 seeds).

Around this point and when one of your whiskerblooms has 10 ticks left to mature, plant a shimmerlily close to it.
-Once your whiskerblooms mature, scum both a Chimerose and a Nursetulip.
-Harvest the Whiskerblooms (26 seeds) and Shimmerlily once you accomplish this.

Very soon after this, you should manage to have all your Queenbeets on the lower side of the garden mature simultaneously.
-Swap to Wood Chips and scum a Juicy Queenbeet (or two if you really hate yourself) and a Duketater. Swap back to fertilizer once you manage this.
-You can harvest the remaining Queenbeets during a combo or something, but don't hold your breath.
-Harvest the Chimerose once it matures (27 seeds)
-Harvest the Nursetulip once it matures (28 seeds).

After some more time, your elderwort will have ~14 ticks left to mature. Plant a crumbspore next to it at this point.

-Once your elderwort finally matures, swap to wood chips and scum an Ichorpuff. Harvest the Elderwort for its seed (29 seeds).
Immediately surround your Queenbeets with elderworts. Depending on your duketater, ichorpuff, and Drowsyfern positions you might have 1-4 eligible spots
where you can spawn an Everdaisy (your last plant) on the upper plant on the garden. Plant Elderworts in a row accordingly.
-Harvest the Ichorpuff once it's mature (30 seeds) and wait a bit for your elderworts to mature.

Once your elderworts have matured a bit, plant Tidygrasses accordingly so you maximize the number of plots where an Everdaisy can spawn.
Once your Elderworts and Tidygrasses are mature, use Wood Chips to spawn an Everdaisy.
Your Drowsyfern should finally be mature around this point; harvest it (31 seeds).
Your Duketater will follow and mature as well, harvest it (32 seeds)

Swap to fertilizer, surround the everdaisy with elderworts and wait for your remaining 2 plants to be mature. Harvest the everdaisy (33 seeds) and the
Juicy Queenbeet (34 seeds). At this point you can scum the ticks to make the process more efficient.

Congratulations, you have completed the garden in a very efficient manner! Sacrifice it to the hornets and repeat the process for even more lumps.